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From https://archive.org/details/climateconsider03wardgoog/page/n381/mode/1up
by Ward, Robert DeCourcy, 1867-1931
1918
PREFACE
TTHE preparation of a volume on Climate for The
? * Science Series was suggested to me by the
|- Editors in Octóber, 1904. I was asked to prepare a
j book “ which can he read by an intelligent person who
has not had special or extended training in the tech-
< nicalities of the Science, . . . the book to be such
as would not compete with strictly meteorological
text-books, but to handle the broad questions of
climate.” It so happened that it was then already in
my mind to prepare a book dealing with certain large
relations of climate, which might serve as supple-
0 mentary reading for the students in my course on
General Climatology in Harvard University. The
present volume is an attempt on my part to write
a book which shall meet the wishes of the Editors of
The Science Series and at the same time fit the needs
of my students.
Climate is based on lecture-notes which have been
accumulating for the past ten years. It does not
attempt to present any very new or original material,
but it does aim to co-ordinate and to set forth clearly
and systematically the broader facts of climate in
such a way that, as desired by the Editors, the gen-
eral reader, although not trained “ in the technicali-
ties of the sdence,” may find it easy to appreciate
iii
I
iv
PBEFACE
»
them. At the same time, the needs of the teacher
and student have been kept constantly in mind, and
the subject-matter has been arranged in such a way
as seems best to adapt it for purposes of thorough
study.
Climate may be considered in a way as supplement-
ing the first volume of Dr. Julius Hann’s Handbuch
der Klimatologie, an English translation of which
was prepared by me and published in 1903. In that
book, the Standard work of its kind in the world, the
principles of climatology are clearly set forth. My
present volume deals with matters which are either
omitted altogether in the Handbook, or else are very
briefly treated therein. Climate is wholly independ-
ent of Hann’s splendid work, except in so far as my
study of that book inspired me to prepare this one.
The general scope and purpose of the different sec-
tions in Climate are as follows. The Introduction
is essentially a very condensed synopsis of the first
six chapters of Hann’s first volume, with the addition
of some other matter. Chapter I gives a sketch of
the classification of the zones. Chapters II and III
give a brief summary of the general climatic types
which result from the control of land and water, and
of altitude, over the more important elements of
climate. Chapters IV, V, and VI are intended to
give an outline of the climatic characteristics of the
zones in a simple and vivid form, with the least pos-
sible use of tabular matter. For further general in-
formation on this subject, reference may be made to
PBEFACE
T
the world-charts of temperature, winds, cloudiness,
rainfall, etc., given with greater or less completeness
in the various text-books of meteorology, and, very
fully, in the Atlas of Meteorology. In Chapter VII
the attempt is made to give a survey of some of the re-
lations between weather and climate and a few of the
more important diseases. Little information on this
subject is readily accessible to the general reader.
The life of man in the tropics, the temperate zones,
and the polar zones is considered in Chapters VIII
to X. No attempt has been made to discuss this
subject in detail, for to do so would far exceed the
limits set for this book. It has rather been my plan
to piek out typical illustrations here and there, as
suggestions. Many of the cases referred to will
probably be familiar to teachers and students of
geography, but the co-ordination of all the examples
by climatic zones and by the natural climatic sub-
divisions of these zones will, it is hoped, tend to give
adequate emphasis to the climatic factor, which has
hitherto been much neglected. The final chapter, on
changes of climate, deals with historie and periodic,
and not with geologie changes. The last phase
of the subject has been fully discussed in many books,
while the former, which are of more interest to most
persons, have received much less attention. The ques-
tion of the influence of forests on climate, which many
readers may expect to find considered in this book, is
omitted because it is adequately taken up in Hann’s
Ilandbook (Vol. I).
vi
PREFACE
I have drawn very freely upon Hann’s Handboek
der Klimatologie, Vols. II and III (2d ed., Stuttgart,
1897), as well as upon his Lehrbuch der Meteorologie
(2d ed., Leipzig, 1906), two books which are so com-
plete in all details that every writer on meteorological
or climatological subjects is inevitably very depend-
ent upon them. The curves in Chapters IV, V, and
VI were all drawn from data given in the Lehrbuch.
In the chapters on the life of man in the different
zones, I have made liberal use of RatzeTs Anthropo-
geographie (2d ed., Stuttgart, 1899). The Princi-
pal references other than these are the following:
W. M. Davis: Elementary Meteorology (Boston,
1902); A. J. and F. D. Herbertson: Man and His
Work (London, 1899); W. Koppen: Klimakunde.
I. Allgemeine KUmalehre (2d ed., Leipzig, 1906);
A. Supan: Grundzüge der physischen Erdkunde (3d
ed., Leipzig, 1908); W. Trabert: Meteorologie und
Klimatologie (Leipzig and Vienna, 1905); W. J.
van Bebber: Hygiënische Meteorologie (Stuttgart,
1895); A. Woeikof: Die Klimate der Erde (Jena,
1887); Atlas of Meteorology (Edinburgh, 1899).
I am indebted to the publishers, Messrs. 6. P.
Putnam’s Sons, for their generous permission to me
to use certain parts of this book in an article pre-
pared for the Encyclopeedia Britannica in 1906, as
well as for the privilege which they willingly accorded
me of publishing as separate articles many of the
chapters induded in this book. Chapters I to III
have appeared in the BuÜetin of the American
PREFACE
VÜ
Geographical Society; Chapters IV to VI in the
Journal of Geography; Chapter VII in the Bulletin
of the Geographical Society of Philadelphia, and
Chapter XI in the Popular Science Monthly. My
thanks are also due to my fellow-workers, Professors
Hann, Mohn, Supan, Koppen, Angot, and W. M.
Davis, and also to Dr. Fridtjof Nansen, for permis-
sion to reproduce some of their maps and diagrams in
the present volume. Mr. Henry S. Mackintosh, of
Keene, N. H., has very kindly helped me in the proof-
reading.
ROBERT DE C. WARD.
Harvard University,
Cambridge, Mass.,
December, 1907.
CONTENTS.
PAGB
Intboduction.....................................1
Meaning and scope of climatology—Relation of
meteorology and climatology—Literature of climatol-
ogy—The climatic elements and their treatment—
Solar climate—Physical climate.
CHAPTER I.
The Climatic Zones and theib Subdivisions . 19
Classification by latitude circles: the five classic
zones; klima as used by the Greeks; Ptolemy’s cli-
mates; Parmenides; Polybius; Posidonius; Aristotle;
Eudoxus; Strabo; Hippocrates—Temperature zones:
Supan ; Koppen; Gebelin—Wind zones: Davis;
Woeikof — Summary and conclusions—Necessary
subdivisions of the zones.
CHAPTER IL
The Classification of Climates .... 35
Need of a classification of climates—Relation of
Continental andocean areas to temperature: reasons
for the slow change in the temperature of ocean
waters—Marine or oceanio climate—Continental cli-
mate—Desert climate—Coast or littoral climate—
Monsoon climate—Mountain and plateau climate—
Mountains as climatic divides.
CHAPTER HL
Tiie Classification of Climates (Continued) . . 55
Supan’s climatic provinces—Köppen’s classifica-
ix
X
CONTENTS
tion of climates—Ravenstein’s hygrothermal types—
Classification of rainfall systems—Herbertson’s nat-
ural geographical regions—Summary and conclu-
sions.
CHAPTER IV.
The Chabacteristics of the Zones. I. The Tbopics
General: climate and weather—Temperature—The
seasons—Physiologioal effects of heat and humidity
—Pressure—Winde and rainfall—Land and sea
breezes —Thunderstorms—Clondiness—In ten si ty of
sky-light and twilight—Climatic subdivisions: L
The equatorial belt—II. Trade wind beits—UI. Mon-
soon beits—IV. Mountain climate.
CHAPTER V.
The Chabacteristics of the Zones. IL The Tem-
pebate Zones..............................
General : “ Temperate” zones—Temperature —
Pressure and winde—Rainfall—Humidity and cloud-
iness—Seasons: their effects on man—Weather—
Climatic subdivisions—South temperate zone—Sub-
tropical beits: Mediterranean climates—North tem-
perate zone : Western coasts—Interiors—Eastera
coasts—Mountain climates.
CHAPTER VL
The Chabacteristics of the Zones. ni. The Polar
Zones ....................................
General: relation to man, animals, and plants—
Temperature—Pressure and winds—Rain and snow
—Humidity, doudiness and fog — Cyclones and
weather—Twilight and optical phenomena—Physi-
ological effects.
CHAPTER VII.
The Hygiene of the Zone£......................
Introduction: some general relations of climate and
health—A complex subject—Climate, micro-organ-
CONTENTS
PAGB
isme, and disease—Geographical distribution of dis-
ease—Tropics: general physiological effects—Trop-
ical death rates—Hygiene in the tropics—Tropical
diseases—Malaria—Yellow fever—Dysentery: diar-
rhceal disorders—Tropical abscess of the liver—
Cholera—Plagne—Sunstroke and related conditions
—Dengue—Beri-beri—Other minor diseases—Gen-
eral conclusions: tropics—Temperate zones: gen-
eral—Winter and summer diseases—Tuberculosis—
Pnenmonia—Diphtheria—Influenza— Bronchitis—
Rheumatism—Measles and scarlet fever—Typhoid
fever—Whooping cough —Cholera infantum—Hay
fever—Polar zones: general—Scurvy—Climate and
health: general conclusion.
CHAPTER VUL
The Life of Man in the Tbopics .... 220
Climate and man: general—Some old views re-
garding the effects of climate on man—Factors in
the problem other than climate—Climate and habit-
ability—The development of the tropics—The labour
problem in the tropics—The government of tropical
possessions—Primitive civilisation and the tropics—
Dwellings in the tropics—Clothing in the tropics—
Food in the tropics—Agriculture, arts, and industries
in the tropics—Some physiological effects of tropical
climates—The equatorial forests—The open grass-
lands of the tropics: savannas—Trade wind beits on
land: the deserts—Trade wind beits at sea—Mon-
soon districts—Tropical mountains.
CHAPTER IX.
The Life of Man in the Tempebate Zones . . 272
Climate and man in the temperate zones: general /
—Northward movement of civilisation in the north
temperate zone—Present-day migrations within the
xu
CONTENTS
PAGB
temperate zones—Tlie continents and the temperate
zone—Differences between northerners and south-
erners—Variety of conditions in the temperate zones:
classification—Life of man in the forests of the tera-
perate zone—Forest clearings—The steppes —Cli-
mates and crops in the temperate zones—The deserts
—Mountains—Climate and weather: some mental
effects—Climate and weather and military operations
—Railroads — Tran sportation by water—Various
effects of the weather.
CHAPTER X.
The Life of Max ix the Polak Zoxes . . . 322
General: a minimum of life—Culture—Subdivisions
of the Arctic zone—Characteristics of the tundra—
The reindeer—Population and occupations—Dwell-
ings—Food and clothing—Iceland—The polar ice
cap: the Eskimo—Dwellings—Food and clothing—
Travel and transportation—Occupations and arts—
Customs—Deserts of sand and deserts of snow.
CHAPTER XI.
Changes of Climate.............................338
Popular belief in climatic change—Evidence of
climatic changes within historie times—What mete-
orological records show—Why the popular belief in
climatic changes is untrustworthy—Value of evi-
dence concerning changes of climate—Periodic oscil-
lations of climate: the sunspot period—Brückner’s
35-year cycle—Climatic cycles of longer period—
Geological changes in climate—Conclusion.
Index
3G5
PAGB
8
10
14
22
25
27
39
48
50
56
63
64
65
66
67
G8
69
ILLUSTRATIONS.
Distribution op Insolation over the Earth
Annual Variation op Insolation at Different
Latitudes..............................
Insolation Received at Different Latitudes
on Junk 21...............................
The Zones in the Time op Parmenidks
Supan’s Temperature Zones . . . .
Temperature Zones after Koppen
Influence op Land and Water on the Annual
March of Air Temperature ....
Diurnal Vabiation op Pressure: Influence op
Altitude.................................
Diurnal Yariation op Temperature: Influence
op Altitude..............................
Supan’s Climatic Provinces................
General Distribution op Plant Zones
Sciieme op Climates at Sea-Level
Names op Climates at Sea-Level
Yertical Distribution op Climates
Prr8sure and Winds in Janu art
Pressure and Winds in July .
Köppen’s Classification of Climates in Rela-
tion to Vegetatiox ................
xiii
ILLUSTRA TIONS
xiv
FIO. PAGB
18 Herbertson’s Major Natural Regions . . 71
19 Annual Marcii of Temperature: Equatorial
Type...................................91
20 Annual March of Rainfall in the Tropics • 92
21 Annual March of Cloudiness in the Tropics . 95
22 Annual March of Temperature: Tropical Type 97
23 Monthly Distribution of Rainfall: Sub-Tropi*
cal Winter Rains.......................125
24 Rainy and Rainless Zones on Eastern Atlan-
tic Co ast.............................128
25 Annual March of Temperature for Selected
Süb-Tropical Stations . 131
26 Annual March of Cloudiness in a Sub-Tropi-
cal Climate............................133
27 Annual March of Temperature for Selected
Stations in the Temperate Zones . . . 135
28 Annual March of Rainfall: Temperate Zones 139
29 Annual March of Cloudiness in Continental
and Mountain Climates: Temperate Zones . 147
30 January North Polar Isotherms . . . 155
31 July North Polar Isotherms . . . .156
32 Mean Annual North Polar Isotherms . . 158
33 Annual March of Temperature: Polar Type . 164
34 Annual March of Cloudiness in the North
Polar Zone: Marine Type .... 173
ACKNOWLEDGMENT OF ILLUSTRATIONS.
Fig. 1. W. M. Davis: Elementary Meteorology.
“ 2, 8, 7, 8, 9. A. Angot: Traité élémentaire de Météorologie.
“ 4. H. Berger: Oeschichte der wissenschaftiichen Erdkunde der
Qriechen.
“ 5,10, 24. A. Supan: QrundzÜge der physischen Erdkunde. 8d
edition.
“ 6. W. Koppen: Die Wdrmezonen der Erde, nach der Daver der
beween, gemdssigten und katten Jahreezeit, und nach der
Wirkung der Wdrme auf die organische Wélt betrachtet.
Met. Zeitschr., i, 1884.
“ 11,12,18,14,15,16,17. W. Kóppen: Versuch einer Klassiflkation
der Klimate, vorzugsweise nach ihren Beziehungen zur
Pflanzenwelt. Hettner’s Oeogr. Zeitschr., vi, 1900.
“ 18. A. J. Herbertson: The Major Natural Regions. Oeogr. Jour.,
zxv, 1905.
“ 80, 81, 82. Scientiflc Results of the Nonvegian North Polar Expedi-
tian. Vol. vi, Meteorology.
xv
CLIMATE
INTRODU CTION
Meaning and Scope of Climatology—Relation of Meteorology and
Climatology—Literature of Climatology—The Climatic Ele-
ments and their Treatment—Solar Climate—Physical Climate.
Meaning and Scope of Climatology. The word
klima (from xMvetv, to incline), as used by the
Greeks, originally referred to the supposed slope of
the earth toward the pole, or to the inclination of the
earth’s axis or of the sun’s rays. It may, perhaps,
have had reference to the different exposures of
mountain slopes. Later, probably after Aristotle’s
time, it came to be used as about equivalent to our
zone, but at first it was simply a mathematica! or an
astronomical term, not associated with any idea of
physical climate. A change of latitude in those days
meant a change of climate. Such a change was
gradually seen to mean a change of atmospheric con-
ditions as well as a change in length of day. Thus
klima came to have its present meaning.
An excellent illustration of the ancient meaning of
2
INTRODUCTJON
the word klima is found in the system of climates pro-
posed by the famous geographer, Ptolemy. This
was a division of the earth’s surface between equator
and north pole into a series of climates, or parallel
zones, separated by latitude circles and diifering from
one another simply in the length of their longest day.
Ptolemy’s subdivision of the earth’s surface was really
nothing but an astronomical climatic table.
Climate, as we use the term, is the resultant of the
average atmospheric conditions, or, more simply, it
is the average condition of the atmosphere. Weather
is a single occurrence, or event, in the series of condi-
tions which make up the climate. The climate of a
place is in a sense its average weather. The average
values of these atmospheric conditions can be deter-
mined only by means of careful observations, con-
tinued for a period sufficiently long to give accurate
results. Climatology is the study or Science of
climates.
Relation of Meteorology and Climatology. Mete-
orology and climatology are interdependent. It is
impossible to distinguish very sharply between them.
Each needs the results obtained by the other. In a
strict sense, meteorology deals with the physics of
the atmosphere. It considers the various atmo-
spheric phenomena individually, and seeks to deter-
mine their physical causes and relations. lts view is
largely theoretical. The aspect of meteorology which
is of most immediate practical importance to man is
that which concerns weather-forecasting.
INTRODÜCTION
3
When the term meteorology is used in its broadest
meaning, climatology is a subdivision of meteorology.
Climatology is largely descriptive. It aims to give
as clear a picture as possible of the interaction of the
various atmospheric phenomena at any place on the
earth’s surface. It rests upon physics and geogra-
phy, the latter being a very prominent factor. Cli-
matology may almost be defined as geographical
meteorology. lts main object is to be of practical
service to man. lts method of treatment lays most
emphasis on the eleinents which are of the most im-
portance- to life. Climate and crops, climate and
industry, climate and health, are subjects of vital
interest to man. No other science concerns man more
closely in his daily life.
Literature of Climatology. Scientific climatology
is based upon numerical results obtained by system-
atic, long-continued, and accurate meteorological
observations. The essential part of its literature is
therefore found in the collections of data published
by the various meteorological services and observator-
ies. In addition, large numbers of short sketches and
notes on climate, partly the more or less haphazard
accounts of travellers, partly the more careful studies
of scientific observers, are scattered through a wide
range of geographical and other publications. The
only comprehensive text-book of climatology is the
Handbuch der Klimatologie of Professor Julius
Hann, of the University of Vienna. This is the
Standard book on the subject, and upon it is based
4
-
JNTR0DÜCT10N
much of the present volume, and of other recent
discussions of climate. The second edition of this
work, in three volumes, was published in 1897 (Stutt-
gart, Engelhorn). The first volume deals with gen-
eral climatology, and has been translated into
English.1 The second and third volumes are de-
yoted to the climates of the different countries of the
world. Woeikof’s Die Klimate der Erde (Jena,
Costenoble, 1887) is also a valuable reference book.
The first part concerns general relations of climate,
particularly to rivers and lakes, to vegetation, and to
snow-cover, while the second part deals with the
climates of special areas. The Standard meteorologi-
cal journal of the world, the Meteorologische Zeit-
schrift (Braunschweig, Vieweg, monthly), is indis-
pensable to anyone who wishes to keep in touch with
the latest publications on climatology, for it contains
the most complete record of such literature, as well
as a large number of original notes and discussions.
The newest and most complete collection of charts is
that in the Atlas of Meteorology (London, Con-
stable, 1899), in which also there is an excellent
bibliography. For the titles of more recent pub-
lications reference may be made to the Interna-
tional Catalogue of Scientific Literature (annual
volume on Meteorology); or to the more frequent
bibliographical lists in the Meteorologische Zeit-
schrift; the Monthly Weather Review (Washington.
U. S. Weather Bureau); the Quarterly Journal of
lBy R. De C. Ward. London and New York, Macmillan, 1903.
INTRODÜCTION
6
the Royal Meteorological Society (London), and the
Halbmonatüches IAtteraturverzeichnus der “ Fort-
schritte der Physik ” (B raunschweig, Vieweg, twice
a month).
The Climatic Element8 and their Treatment.
Climatology has to deal with the same groups of at-
mospheric conditions as those with which meteorology
is concerned, viz.: temperature (including radiation);
moisture (including humidity, precipitation, and
cloudiness); wind (including storms); pressure;
evaporation, and also, but of less importance, the
composition and the Chemical, optical, and electrical
phenomena of the atmosphere. The characteristics
of each of these so-called climatic element$ are set
forth in a Standard series of numerical values, based
on careful, systematic, and long-continued meteoro-
logical records, corrected and compared by well-
known methods. Various forms of graphic presen-
tation, by curves, or by wind roses, etc., are employed
to emphasise and simplify the numerical results.
Instructions concerning the use, exposure, hours of
observation, and corrections of the ordinary meteoro-
logical instruments; as well as for obtaining the
usual numerical results, are published by the various
govemmental meteorological services. In Hann’s
Handbook of Climatology, Vol. I, will be found a
general discussion of the methods of presenting the
different climatic elements, and of the reasons for
adopting the accepted scheme of presentation. The
most complete guide in the numerical, mathematical,
6
INTR0DÜCT10N
and graphic treatment of meteorological data for
climatological purposes is Hugo Meyer’s Anleitung
zur Bearbeitung meteorologücher Beobachtungen
für die Klimatologie (Berlin, Springer, 1891).
Climate deals first of all with average conditions,
as is apparent from the definition given above. But
means may be made up of very different values of the
elements which go into them, and therefore a satis-
factory presentation of a climate must include more
than mere averages. It must take account, also*, of
regular and irregular daily, monthly, and annual
changes, and of the departures, mean and extreme,
from the average conditions which may occur at the
same place in the course of time. The mean mini-
mum and the mean maximum temperature or rainfall
of a month, or a season, are important data, nót in any
way replaced by a knowledge of the mean monthly
or seasonal temperature and rainfall. Further, a
determination of thé frequency of occurrence of a
given condition, or of certain values of that condition,
is important, for periods of a day, month, or year, as,
for example, the frequency of winds according to
direction or velocity; or of different amounts of
cloudiness; or of temperature changes of 5, or 10,
or more degrees; the number of days with and with-
out rain or snow in any month, or year, or with rain
of a certain amount, etc. The probability of occur-
rence of any condition, as of rain in a certain month;
or of a temperature of 82°, for example, is also a
useful thing to know conceming a climate. In the
INTBODÜCTION
7
past, climatology has been too much concemed with
monthly, seasonal, and annual averages. An im-
portant addition to the usual climatic summaries
would be the introduction, for all regions in which the
cyclonic or storm control of weather conditions is
characteristic, of the cyclonic unit, so that, for ex-
ample, the average duration and value of cyclonic
ranges of temperature in the several months, or the
proportion of the annual rain and snowfall received
from cyclonic storms and from local thunderstorms,
might be determined.1
Solar Climate. The sun is clearly the principal
control of climates on the earth’s surface. The gen-
eral distribution of temperature, as well as the sea-
sonal and diurnal changes, all depend upon changes
in the intensity of sunshine. Hence a brief considera-
tion of the distribution of insolation over the earth’s
surface is essential to a proper understanding of cli-
mates. Climate, in so far as it is controlled solely by
the amount of solar radiation which any place receives
by reason of its latitude, is called solar climate.
Clearly, all places on the same latitude drcle would
have the same solar climate, for the intensity and
amount of insolation depend upon the angle of in-
cidence of the sun’s rays, and upon the length of day,
and both of these depend upon latitude. Solar cli-
mate alone would prevail if the earth had a homo-
1 See R. DeC. Ward: Suggestions Conceming a More Rationa!
Treatment of Climatology. Report Eighth International Geo-
graphic Congress, Washington, D. C., 1904, pp. 277-298.
8
IXTRODUCTION
geneous land surface, and if there were no
atmosphere. For under these conditions, and with-
out air or ocean currents, the distribution of tem-
perature at any place would depend solely on the
amount of energy received from the sun, and upon
the loss of heat by radiation. And these two factors
would have the same value at all points on the same
latitude circle.
The relative amounts of insolation received at dif-
ferent latitudes and at different times have been care-
fully determined. The values all refer to conditions
at the upper limit of the earth’s atmosphere, i. e.,
Fig. i. Distribution of Insolation over the Earth
without the effect of absorption by the atmosphere.
The accompanying diagram (see Fig. I) shows very
clearly the distribution of insolation in both hemi-
INTRODÜCTION
9
spheres at different latitudes and at different times in
the year. The latitudes are given at the left margin
and the time of year at the right margin. The values
of insolation are shown by the vertical distance above
the plane of the two margins.
At the equator, where the day is always twelve
hours long, there are two maxima of insolation at the
equinoxes, when the sun is vertical at noon, and two
minima at the solstices, when the sun is farthest off
the equator. The annual curves show that the values
do not vary much through the year, because the sun
is never very far from the zenith, and day and night
are always equal. There is a slight difference in the
insolation at the two maxima, owing to a difference
in the sun’s distance, the earth’s orbit being an ellipse
and not a circle. The earth is nearer the sun in the
winter of the northem hemisphere, and therefore the
spring maximum is somewhat greater than the au-
tumn maximum. The varying distance from the sun
also explains the fact that the maxima of insolation
do not come exactly on the dates of the equinoxes.
These conditions are clearly brought out in curve
1 of Fig. 2, which shows the annual march of insola-
tion on the equator. The law of the distribution of
insolation would be simple if the sun were always on
the equator, for the angle of insolation and the length
of day and night would then always remain the same.
But under existing conditions, both the angle of in-
solation and the length of day are constantly chang-
ing, and the interaction between these two Controls •
10
INTRODÜCTION
becomes very complex. As the latitude increases, the
angle of insolation becomes more oblique, and the
intensity of insolation decreases, but at the same time
the length of day rapidly increases during the sum-
mer, and towards the pole of the hemisphere which is
having its summer the gain in insolation from the
Jan. Feb. Mar. Apr. MayJuneJuly Aug. SeptOct. Nov. Dec.Jan.,
Fig. 2. Annual Variation of Insolation at Different Latitudes
latter cause more than compensates for the loss by
the former. The doublé period of insolation, above
noted for the equator, prevails as far as about lat. 12®
N. and S.; at lat. 15° the two maxima have united,
1NTRÓDÜCTIÓN
11
and the same is true of the minima. Take the
case of an intermediate latitude, like 45° N. (see
curve 2, Fig. 2). Here there is one minimum, in
December, when the sim is south of the equator, and
one maximum, in June, when the sim is north. The
slight displacement of this maximum and minimum
from the exact date ct£ the two solstices is due to the
difference in the sun’s distance. At the north pole
(curve 8, Fig. 2), there is one maximum at the
summer solstice, and no insolation at all while the sun
is below the horizon. The distribution of insolation
at different latitudes on the same day is also interest-
ing. On June 21, for example (see Fig. 1), the
equator has a day twelve hours long, but the sun’s
maximum altitude is only 66^°, t. e.t it does not
reach the zenith, and the amount of insolation
is less than at the equinox. On the northem
tropic, however, the sun is vertical at noon, and the
day is between thirteen and fourteen hours long.
Hence the amount of insolation received at this lati-
tude on June 21 is greater than that received on the
equinox at the equator. As one passes from the
tropic to the pole the sun stands lower and lower
at noon, and the value of insolation would
steadily decrease with latitude if it were not
for the increase in the length of day. Going pole-
wards from the northem tropic on June 21, the
value of insolation increases for a time, because, al-
though the sun is lower, the number of hours during
which it shines is greater. A maximum value is
12
INTR0DUCT10X
reached at about lat. 43%° N. The decreasing alti-
tude of the sun then more than compensates for the
increasing length of day, and the value of insolation
diminishes, a minimum being reached at about lat.
62°. Then the rapidly increasing length of day to-
wards the pole (the day being twenty-four hours long
beyond the Arctic circle) again brings about an in-
crease in the value of insolation, until a maximum is
reached at the pole which is greater than the value re-
ceived at the equator at any time. (See Fig. 2, in
which the curves are all drawn on the same scale).
The length of day is the same on the Arctic circle
as at the pole itself, but while the altitude of the sun
varies during the day on the former, being at the hori-
zon at midnight and highest at noon, the altitude at
the pole remains 231/2° throughout the twenty-four
hours. The result is to give the pole a maximum
(See Fig. 8, curve marked 1.00.). On June 21, there
are therefore two maxima of insolation, one at lat.
481/2° and one at the north pole. From lat. 481-4°
N., insolation decreases to zero on the Antarctic
circle, for sunshine falls more and more obliquely,
and the day becomes shorter and shorter. Beyond
lat. 66%° S. the night lasts twenty-four hours. On
December 21 (see Fig. 1), the conditions in southem
latitudes are similar to those in the northem hemi-
sphere on June 21, but the southem latitudes have
higher values of insolation because the earth is then
nearer the sun.
At the equinox, the days are equal everywhere, but
INTRODUCTION
13
the noon sun is lower and lower with increasing lati-
tude in both hemispheres until the rays are tangent to
the earth’s surface at the poles (except for the effect
of refraction). Therefore, the values of insolation
diminish from a maximum at the equator to a mini-
mum at both poles. From the fact that the Southern
hemisphere has its summer in perihelion and its win-
ter in aphelion, it follows that there is a greater dif-
ference between the seasonal values of insolation south
of the equator than north of it. In other words, the
solar climate of the Southern hemisphere is more se-
vere than that of the northem. Nevertheless, owing
to the fact that the earth moves more rapidly around
its orbit when nearest the sim, both hemispheres re-
ceive equal amounts of insolation at the same lati-
tudes, and in the mean of the year, both have the same
amount of insolation.
The values of insolation thus far considered have
reference to the upper limit of the earth’s atmosphere,
or to the earth’s surface assuming that no atmosphere
exists. The effect of the atmosphere is to weaken the
sun’s rays. The more nearly vertical the sun, the less
the thickness of atmosphere traversed by the rays.
The values of insolation at the earth’s surface, after
passage through the atmosphere, have been calcu-
lated. They vary much with the condition of the air,
as to dust, clouds, water vapour, etc. In Fig. 2, the
broken lines, 4, 5, and 6, show the values of insolation
at the equator, lat. 45° N., and the north pole, allow-
ing for a loss of 25% during the passage through the
14
INTRODÜCTION
atmosphere, i. e., with a coëfficiënt of transmission
0.75. This is higher than that usually observed, even
under very favourable conditions, with the sun in the
zenith. As a rule, even when the sky is clear, about
one-half of the solar radiation is lost during the day
Fig. 3. Insolation Received at Different Latitudes on June 21
by atmospheric absorption. The great weakening of
insolation at the pole, where the sun is very low, is
especially noticeable. The effect of the atmosphere
is also shown in Fig. 8. The upper curve represents
INTRODUCTION
15
the total quantity of insolation received at the earth’s
surface with a coëfficiënt of transmission of 1.00
(t. e.j no loss). Under such conditions, as already
noted, there are two maxima on June 21, at lat. 431/2°
N. and at the north pole. The second curve cor-
responds to a coëfficiënt of transmission of 0.75, which
is also used in the broken curves of Fig. 2. Under
these conditions, there is but one maximum, at about
lat. 86° N., and the north pole has only 49% of the
total radiation emitted by the sun. The third curve
is based on a coëfficiënt of transmission of 0.50, and
shows one maximum at lat. 32° N., the pole receiving
only 18% of the total amount which reaches the upper
limit of the atmosphere at that point. The curves
O. 75 and 0.50 show that, taking the atmosphere into
account, even in midsummer the amount of insolation
decreases from between lats. 80° and 40° to the pole.
The following table (after Angot) shows the effect
of the earth’s atmosphere (coëfficiënt of transmis-
sion 0.7) upon the value of insolation received at sea
level.
VALUES OF DAILY INSOLATION AT THE UPPEB LIMIT OF THE
eabth’s atmosphere and at sea level.
Lat. Upper limit of atmosphere Earth’s surface
Equator 40° N. Pole Equator 40° N. Pole
Winter Solstice . 948 360 0 552 124 0
Equinoxes . 1000 773 0 612 411 0
Summer Solstice. 888 1115 1210 517 660 494
16
INTROD ÜCT10N
The following table gives, according to Zenker,
the relative thickness of the atmosphere at different
altitudes of the sun, and also the amount of trans-
mitted insolation.
BELATIVB DI8TANCES TBAVEH8ED BT SOLAR RAYS THROUGH THE
ATHOSPHERB, AND INTENSITIES OF RADIATION PER UNIT AREAS
Altitude of Sun.
o° I 5° I io° I 20° I 30° I 40° I 50° | 6o° | 70° | 8o° | 90°
Relative Lengths of Path through the Atmosphere.
44.7110.8 I 5.7 I 2.92 I 2.00 I 1.56 11.31 I 1.15 ] 1.06 I 1.02 I 1.00
Intensity of Radiation on a Surface Nor mal to the Rays.
0.0 | 0.15 | 0.31 10.51 | 0.62 | 0.68 | 0.72 | 0.75 | 0.76 | 0.77 | 0.78
Intensity of Radiation on a Horizontal Surface.
0.0 I 0.01 I 0.05 I 0.17 I 0.31 I 0.44 I 0.55 I 0.65 I 0.72 1 0.76 I 0.78
Physical Climate. It is clear that the distribution of
insolation, just considered, explains many of the large
facts of the distribution of temperature—for example,
the decrease of temperature from equator to poles;
the doublé maximum of temperature on and near the
equator; the increasing seasonal contrasts with in-
creasing latitude, etc. But it is equally apparent that
the distribution of temperature often does not follow
the distribution of insolation closely, for, if it did
so, the two poles would be warm at the times of their
respective maxima of insolation. The high values of
insolation at the poles do not correspond to high tem-
peratures, as will be seen in a later chapter (VI).
IXTRODUCTION
17
The old view which thus explained an “open polar
sea” was erroneous. The distribution of insolation
suggests a subdivision of the earth’s surface into
three distinct beits. In one, within about 12° of the
equator, there are two maxima and two minima. In
a second, there is one maximum; and for part of the
year the absence of the sun reduces the amount to
zero. In a third, the conditions are intermediate;
there is one maximum and one minimum, but there is
no time when the value of insolation decreases to
zero. Of the second and third of these beits, there are
two divisions, one in the northern and one in the
southem hemisphere. It will be noted that the
tropics, the polar, and the temperate zones roughly
correspond to these insolation beits.
The regular distribution of solar climate between
equator and poles which would exist on a homogene-
ous earth, whereby similar conditions prevail along
each latitude circle, is very much modified by the un-
equal distribution of land and water; by differences
of altitude; by air and ocean currents; by varying
conditions of cloudiness, and so on. Hence the cli-
mates met with along the same latitude circle are no
longer all alike. Solar climate is greatly modified by
atmospheric conditions and by the surface features of
the earth, and what is known as physical climate is
the result. The uniform latitudinal arrangement of
solar climatic beits is interfered with. Physical cli-
mate results from the reaction of the earth’s surface
features upón the atmosphere. According to the
18
-
INTRODUCTION
dominant control, in each case, we have solar, Conti-
nental, marine, and mountain climates. In the first
named, latitude is the essential; in the second and
third, the effect of land or water; in the fourth, the
effect of altitude.
CHAPTER I
THE CLIMATIC ZONES AND THEIR SUBDIVISIONS
Classification by Latitude Circles: The Five Classic Zones; Klima
as Used by the Greeks; Ptolemy’s Climates; Parmenides;
Polybius; Posidonius; Aristotle; Eudoxus; Strabo; Hippoc-
rates—Temperature Zones: Supan; Koppen; Gebelin—Wind
Zones: Davis; Woeikof—Summary and Conclusions—Neces-
sary Subdivisions of the Zones.
Classification by Latitude Circles. So great is the
variety of climates to be found in different parts of
the world that it has long been customary to classify
these climates roughly into certain broad beits.
These are the climatic zones. A simple grouping of
this kind can, however, obviously take account only
of the most general characteristics of the climates
which are included within each zone. The five zones
with which we are most familiar are the so-called tor-
rid, the two temperate, and the two frigid zones. The
torrid, or, better, the tropical zone, naming it by its
boundaries, is limited on the north and south by the
two tropics of Cancer and Capricorn, the equator
dividing the zone into two equal parts. The temper-
ate zones are limited towards the equator by the
tropics, and towards the poles by the Arctic and Ant-
arctic circles. The two frigid, or, better, the two polar
*9
20
CLIMATE
zones, are caps covering both polar regions, and
bounded on the side towards the equator by the Arctic
and Antarctic circles.
These five zones are classified on purely astronomi-
cal or mathematical grounds. They are really zones
of sunshine, or of solar climate. Within the tropical
zone, the sim reaches the zenith at two different times
in the year; its greatest possible zenith distance is
47°; the day is never less than ten and a half hours
long. On the tropics themselves, the sun reaches the
zenith but once a year. In the polar zones, the sun is
below the horizon for twenty-four hours at least once
in winter, and is above the horizon for the same length
of time at least once in summer. On the polar circles,
the noon altitude of the sun decreases to 0° on the
shortest day. The temperate zone has conditions be-
tween these two extremes. At no point can the sun
be in the zenith; nor, except on the polar circles, is
there ever anywhere a twenty-four-hour day or night.
The tropical zone has the least annual variation of
insolation. It has the maximum annual amount of
insolation. lts annual range of temperature is very
slight. It is the summer zone. Beyond the tropics
the contrasts between the seasons rapidly become
more marked. The polar zones have the greatest
variation in insolation between summer and win-
ter. They also have the minimum amount of insola-
tion for the whole year. They may well be called the
winter zones, for their summer is so short and cool
that the heat is insufficiënt for most forms of vegeta-
CLIMATIC ZONES AND SUBDIVISIONS 21
tion, especially for trees. The temperate zones are
intermediate between the tropical and the polar in
the matter of annual amount and of annual variation
of insolation. Temperate conditions do not char-
acterise these zones as a whole. They are rather the
seasonal beits of the world. These five zones further
differ more or less from one another in the character
of their animals and plants, and in the conditions of
human life within their boundaries.
Taking the area of a hemisphere as unity, the rela-
tive areas of these zones are as follows:
Tropical .................. 0.40
Temperate ................. 0.52
Polar ..................... 0.08
This subdivision of the earth’s surface on the basis
of the geometrical distribution of sunshine dates
from the time of the early Greek philosophers and
geographers, but it is impossible to determine with
certainty just when and by whom the various sugges-
tions in this connection were made. The famous
geographer Ptolemy, who lived in the second cent-
ury a.d., used different schemes at different times. In
the lower latitudes the breadth of a klima, or zone,
was fixed by the difference of a quarter of an hour in
the length of the longest day, but in higher latitudes
differences of half an hour, an hour, and finally a
month were the determining factors.
Parmenides, who flourished about the middle of
the fifth century b. c., proposed a five-zone division
of the earth’s surface not very unlike our present sys-
22
CLIMATE
tem. These zones were a torrid zone, uninhabitable
because of heat; two frigid zones, uninhabitable be-
cause of cold; and two intermediate zones, of moder-
ate temperature, suitable for man. The exact limits
assigned to these zones are not known with certainty;
but it is reasonable to suppose that the Arctic circle
was even then recognised as a natural boundary for
the north polar zone, and it is pretty clear that the
temperate zone was much smaller, and the torrid zone
much larger, than in our present classification. (See
Fig. é.)
/^idïiiïV
1 fcrrfd Zon* j
Fig. 4. Thb Zones ui
the Time of Parmenides
The exact boundaries of the different zones varied
more or less for some time, as astronomical know-
ledge became more and more exact, and as the habit-
able area of the earth’s surface was gradually ex-
tended, but the scheme was generally adopted by
later writers. Polybius (bom about B.c. 204), how-
ever, divided his torrid zone into two parts by the
equator, and Posidonius (bom about B.c. 135) di-
vided his torrid zone into three parts, making six and
seven zones respectively. Aristotle (bom b.c. 884)
CLIMATIC ZONES AND SUBDIVISIONS 23
limited the torrid zone by the tropics, and the north
temperate zone by the Arctic circle; but there is doubt
whether he really meant the fixed Arctic circle which
we know. He believed both temperate zones habit-
able, thus limiting the uninhabitable area to the
astronomical tropical zone. Eudoxus, of Cnidus,
who lived about b.c. 866, used a division of a quadrant
of the earth’s circumference into fifteen parts, of
which four belonged to the torrid, five to the temper-
ate, and six to the frigid zone. The tropics were
thus fixed at latitude 24°. Strabo (bom about b.c.
54), opposed the prevailing view that the whole of
the belt between the two tropics was uninhabitable,
and also first clearly set forth the opinion that the
temperature decreases with increasing altitude above
sea-level, as well as with increasing latitude. Strabo
also had some fairly distinct ideas regarding local
differences of climate resulting from the influence of
land and water and of mountain barriers, and noted
several effects of climate upon man and upon vegeta-
tion. He appreciated the fact that the zones were
zones of temperature as well as zones of sunshine.
As early as about 400 B.C., Hippocrates had endeav-
oured to show a causal relation between sunshine and
the topography of a district on the one hand and the
characteristics of its inhabitants on the other. He
also gave an outline of geographical pathology.1
1 The older views regarding the climates and the habitability of
the five zones were thus stated by Virgil (Georgica, i, 283.239»
translation by Davidson): ** Five zones embrace the heavens;
24
CLIMATE
Temperature Zones. The classification of the
climatic zones on the basis of the geometrical distribu-
tion of sunshine serves very well for purposes of
simple description, but a glance at any isothermal
chart shows at once that the isotherms do not coincide
with the latitude lines. In fact, in the higher lati-
tudes, the former often follow the meridians more
closely than they do the parallels of latitude. The
astronomical zones—». e., the zones of light—there-
fore differ a good deal from the zones of heat. Hence
it has naturally been suggested that the zones be lim-
ited by isotherms rather than by parallels of latitude,
and that a closer approach be thus made to the actual
conditions of climate.
Supan (see Fig. 5) has suggested limiting the hot
belt, which corresponds to the old torrid zone, but is
slightly greater, by the two mean annual isotherms
of 68°—a temperature which approximately coin-
cides with the polar limit of the trade winds and
with the polar limit of palms. The latter is consid-
ered by Grisebach to be the truest expression of a
tropical climate. The hot belt widens somewhat.
over the continents, chiefly because of the mobility of
the ocean waters, whereby there is a tendency towards
an equalisation of the temperature between equator
whereof one is ever glowing with the bright sun, and scorched
forever by his fire; round which the two farthest ones to the right
and left are extended, stiff with cerulean ice and horrid showers.
Between these and the middle zones, two by the bounty of the gods
are given to weak mortals; and a path is cut through both, where
the series of the signs might revolve obliquely.”
CLIMATIC ZONES AND SUBDIVISIONS
25
and poles in the oceans, while the stable lands acquire
a temperature suitable to their own latitude. Fur-
thermore, the unsymmetrical distribution of land in
the low latitudes of the northern and southem hemi-
spheres results in an unsymmetrical position of the hot
belt with reference to the equator, the belt extending
Fig. 5. Supan*s Temperature Zones
farther north than south of the equator. The polar
limits of the temperate zones are fixed by the isotherm
of 50° for the warmest month. This is a much more
satisfactory limit than the mean annual isotherm of
82°, which has also been suggested; for climates dif-
fering very widely from one another are found to
have the same mean annual temperature of 32°. The
latter value has chiefly a theoretical interest, but is
of some practical importance in its relation to the
regions of frozen ground. Summer heat is more im-
26
CLIMATE
portant for vegetation than winter cold; and where
the warmest month has a temperature below 50°,
cereals and forest trees do not grow, and man has to
adjust himself to the conditions in a very special way.
The two polar caps are not symmetrical as regards the
latitudes which they occupy. The presence of ex-
tended land masses in the high northem latitudes
carries the temperature of 50° in the warmest month
farther poleward there than is the case in the corre-
sponding latitudes occupied by the oceans of the
southem hemisphere, which warm less easily and are
constantly in motion. Hence the Southern cold cap,
which has its equatorial limits at about lat. 50° S., is
of much greater extent than the northern polar cap.
So far as this south polar zone is concemed, the pres-
ence or absence of an Antarctic continent is imma-
terial; for such a land mass must be ice-covered, and
hence cannot operate to raise the temperature as in
the case of a land surface to which the sun’s rays have
immediate access. The northern temperate belt, in
which the great land areas lie, is much broader than
the southem, especially over the continents. These
temperature zones have real significance. They em-
phasise the natural conditions of climate more than
can be the case in any subdivision by latitude circles,
and they bear a fairly close resemblance to the old
zonal classification of the Greeks.
In high latitudes, neither the mean annual tempera-
ture nor the temperature of the coldest month is
nearly as important a climatic control over vegetation
27
Fig. 6.
Temperature Zones after Köppen
28
CLIMATE
as is the temperature of summer, from the point of
view of climate as a whole, and especially in relation
to organic life. The summer temperatures deter-
mine habitability, the limits of plant growth, and the
general conditions of human life. Hence, in the
higher latitudes, zones bounded by mean annual
isotherms are no great improvement over zones limited
by latitude circles.
Another classification of temperature zones has
been suggested by Koppen (see Fig. 6). In this,
the length of time during which the tempera-
ture remains within certain fixed limits, these limits
having well-marked relations to organic life, is taken
into account. Two critical daily mean temperatures,
68° and 50°, and the duration of these temperatures
for periods of one, four, and twelve months, are the
factors in this classification. These temperatures are
not reduced to sea-level. A normal duration of a
temperature of 50° for less than a month fixes very
well the polar limit of trees and the limits of agricul-
ture. Near this line are found the last groups of
trees in the tundras. A temperature of 50° for four
months marks the limit of the oak, and also closely
coincides with the limits of wheat cultivation. North
of the tree limit, agriculture ceases, and man’s food is
to be sought very largely in the sea. With the ap-
proach to this line, the period of plant growth is
shortened more ar)d more, agricultural operations be-
come restricted, and occupations of other kinds are
followed. These critical temperatures and their
CLIMATIC ZONES AND SUBDIVISIONS 29
vaiying periods of duration from the basis of the fol-
lowing classification:
1. Tropical belt: all months hot (over 68°). This
is almost altogether within the tropics; it reaches, in
round numbers, from latitude 20° N. to 16 S.
2. Sub-tropical beits: 4 to 11 months hot (over
68°); 1 to 8 months temperate (50°-68°.)
8. Temperate beits: 4 to 12 months temperate.
4. Cold beits: 1 to 4 months temperate; the rest
cold (below 50°).
5. Polar beits: all months cold.
The temperate beits of both hemispheres are
further subdivided into three districts1—the steadily
temperate belt2 is found only on the oceans; the belt
of hot summers8 only on the continents; and the third,
with moderate summers and cold winters,4 extends
around the world, with the exception of a notable in-
terruption over Siberia.
In the second of these subdivisions, except in east-
em North America and Asia, the rainfall is generally
deficiënt; irrigation is more or less necessary, and
deserts and steppes characterise the Continental por-
tions. Only in the monsoon districts of southem and
eastern Asia, of Brazil, and of south-eastem North
America, do we find high temperatures combined with
1AU characterised by having at least four months temperate
(50°-68°)v and not more than four months hot (over 68°).
2 No month over 68° or below 50°.
2 Has temperatures below 50° for one or more months.
4 Has less than four months, but not less than one month,
temperate (50°-68°).
30
CLIMATE
high relative humidity. The third subdivision above
noted is now the chief seat of human development.
Over a large part of the cold belt of the northern
hemisphere, the ground is permanently frozen, thaw-
ing only a little on the surface in summer. Never-
theless, in portions of it trees and hardy cereals grow.
The polar beits are, as a whole, outside the limits of
tree growth.
Another suggestion has been made by Gebelin, who
has proposed to select, as limits of the temperate zone,
certain visible geographical boundaries, in contrast
with the ideal climatic limits based upon the distribu-
tion of sunshine. On the oceans, the tropical circles
serve as acceptable boundaries on the sides towards
the equator, but on the continents the desert beits on
both sides of the tropics are reasonable limits, although
these deserts do not reach the eastem coasts of the
continents. For the polar limits of the temperate
zone, the tundras are chosen on the continents, and the
summer ice-masses on the oceans.
Wind Zone». While a simple classification of the
zones on the basis of temperature is an improvement
upon any rigid scheme of division by latitude circles,
the heat zones emphasise the element of temperature
to the exclusion of such important elements as winds
and rainfall. S>o distinctive are the larger climatic
features of the great wind beits of the world, that a
classification of climates according to wind systems
has been suggested by Davis. As the rain beits of
the world are closely associated with these wind sys-
CLIMATIC ZONES AND SUBDIVISIONS 31
tems, a classification of the zones by winds also em-
phasises the conditions of rainfall. In such a scheme,
the torrid, or tropical zone, with its regularity of
weather through the year, and the comparative sim-
plicity of its climatic features, is bounded on the north
and south by the margins of the trade wind beits, and
is therefore larger than the classic torrid zone. This
trade wind zone is somewhat wider on the eastern side
of the oceans, and properly includes within its limits
the equable marine climates of the eastern margins
of the ocean basins, even as far north as latitude 30°
or 35°.
Most of the eastern coasts of China and of the
United States are thus left in the more rigorous and
more variable conditions of the north temperate zone.
Through the middle of the trade wind zone extends
the sub-equatorial belt, with its migrating calms, rains,
and monsoons. On the polar margins of the trade
wind zone lie the sub-tropical beits, of altemating
trades and westerlies. The temperate zones, with the
great irregularity of their weather phenomena and
their marked seasonal changes, embrace the latitudes
of the stormy westerly winds, having on the equator-
ward margins the sub-tropical beits, and being some-
what narrower than the classic temperate zones.
Towards the poles, there is no obvious limit to the tem-
perate zones, for the prevailing westerlies extend
beyond the polar circles. These circles may, how-
ever, serve fairly well as boundaries, because of their
importance from the point of view of insolation. The
32
CLIMATE
polar zones in the wind classification, therefore, re-
main just as in the older five-zone scheme.
A compromise between the rigid division by lati-
tude circles and the isothermal and wind classifica-
tions has been suggested by Woeikof, who objects to
limiting the torrid zone by the tropics on the ground
that the high temperatures of that zone, as welL as
its characteristic winds, extend beyond these parallels.
Latitude 30° would be a more natural boundary; but
as the westerlies, which are characteristic of the tem-
perate zones, prevail there in winter, latitude 25° is
chosen as a compromise between 23%° and 80°. The
polar zones are bounded by latitude 65°. When
bounded by these several limits, the areas of the dif-
ferent zones are as follows:
Tropical Zone...................... 417
Temperate Zones.....................490
Polar Zones.......................... 93
1000
-
Summary and Conclusions. Reviewing what has
been said regarding the climatic zones, it would seem
that, all things considered, a simple division by iso-
therms, such as that suggested by Supan (1896), is
the best for general use. The early division by lati-
tude circles, while it has the merits of great simplicity,
and emphasises the all-important element of sunshine,
is too arbitrary, and hence does not accord sufficiently
well with the facts of actual climate. Nevertheless, we
should not discard the classic zones without recog-
CLIMATIC ZONES AND SUBDIVISIONS 33
nising that they have a real meaning in relation to
solar climate. The grouping of the climatic zones
according to wind systems has much to recommend it
from a meteorological standpoint, but is not quite
simple enough for general use. Its adoption involves
an understanding of the great wind and calm beits of
the world, and of the migration of these beits. The
shifting of the boundaries of the torrid zone also
brings in an element of uncertainty which is some-
what confusing, although, as a place in the sub-tropi-
cal belt really changes its climate with the seasonal
change from westerlies to trades, and vice versa, it
may reasonably be expected to change its zone. In
other words, actual climatic conditions are recognised;
and in any case, this is a more reasonable plan than to
limit the torrid zone by means of the tropics, which
arbitrarily cut across the trade wind beits and sepa-
rate areas which are climatically the same. The tem-
perature zones proposed by Koppen, while useful in
special studies of plant distribution, are too detailed
for general adoption.
Whatever climatic zones we adopt, we should cer-
tainly abandon the word temperate altogether as the
designation of the middle zone in each hemisphere,
and substitute some such adjective as intermediate
for it. The words torrid and frigid should likewise
disappear, and be replaced by tropical or equatorial,
and polar.
Necessary Subdivisions of the Zones. However
we may classify them, the climatic zones are far from
3
34
CLIMATE
being uniform in character throughout their whole
extent. Hence, no brief, simple description of the
climate of a zone can be given. For this reason, sug-
gestions have been made regarding subdivisions of
the different zones. Thus, in the case of the classic
north temperate zone, it has been proposed to subdi-
vide it into sub-tropical, temperate, and sub-arctic, but
the question how to limit these subdivisions is difficult
to settle. A more rational scheme is that which, in
view of the great differences in the climatic relations
of land and water, recognises a first large subdivision
of each zone into land and water areas. Then, as Con-
tinental interiors diflfer from coasts, and as windward
coasts have climates unlike those of leeward coasts, a
further natural subdivision would separate these dif-
ferent areas. Finally, the control of altitude over
climate is so marked that plateaus and mountains
may well be set apart by themselves as separate clima-
tic districts. If each of the zones, whether bounded
by latitude circles, or by isotherms, or by wind Sys-
tems, be considered under these general subdivisions,
as close an approach to actual conditions of climate
will be made as is possible in general description. Ob-
viously, however, when the larger zones are subdi-
vided to such an extent as is here suggested, we are
dealing with a classification of climates rather than
with climatic zones.
\
l
CHAPTER II
THE CLASSIFICATION OF CLIMATES
Need of a Classification of Climates—Relation of Continental and
Ocean Areas to Temperature: Reasons for the Slow Change in
the Temperature of Ocean Waters—Marine or Oceanic Cli-
mate—Continental Climate—Desert Climate—Coast or Lit-
toral Climate—Monsoon Climate—Mountain and Plateau
Climate—Mountains as Climatic Divides.
Need of a Classification' of Climates. A broad di-
vision of the earth’s surface into zones is necessary as
a first step in any systematic study of climate, but it
is not satisfactory when a more detailed discussion is
undertaken. The reaction of the physical features
of the earth’s surface upon the atmosphere compli-
cates the climatic conditions found in each of the
zones, and makes further subdivision desirable. Un-
der the control of these different physical conditions,
the climatic elements unite to produce certain fairly
distinct types of climate, and these may be classified
in various ways. The usual method is to separate
the Continental (near sea-level) and the marine. An
extreme variety of the Continental is the desert; a
modified form, the littoral; while altitude is so im-
portant a control that mountain and plateau climates
are further grouped by themselves.
35
36
CLIMATE
Relation of Continental and Ocean Areas to Tem-
perature. Land and water differ greatly in their be-
haviour regarding absorption and radiation. The
former warms and cools readily, and to a considerable
degree; the latter, slowly and but little. (1) Of the
insolation which falls upon the ocean, a good deal is
at once reflected, and is therefore not available for
warming the water. Land surfaces, on the other
hand, are poor reflectors; but little insolation is lost
in that way; hence more energy is available for raising
their temperature. (2) Most of the insolation which
enters the water is transmitted to some depth, and,
therefore, is not effectively applied to warming the
surface. Land is opaque and does not allow the in-
cident insolation to pass beyond a comparatively thin
surface stratum; hence this surface can be well
warmed. (3) The evaporation of water requires a
large amount of energy, which changes the state of
the water without raising its temperature (latent
heat). Land, although often moist, is itself non-
volatile; therefore the loss of energy in the process of
evaporation is usually very slight. (4) Water is
more diflicult to warm than any other natural sub-
stance, while land is warmed easily and quickly. If
equal amounts of heat are received by equal areas of
land and water, the former warms about twice as much
as the latter. (5) The mobility of water keeps the
warmer and the colder portions well mixed, and there-
fore greatly retards the process of warming any one
portion of the surface. Land cannot thus equalise
THE CLASSIFICATION OF CLIMATES
87
its temperature. (6) The cloudiness over the oceans
is usually greater than that over the lands, and this
operates to shade the former more than the latter, re-
ducing the energy available for w&rming the water
surface. For these various reasons, ocean surfaces
can warm but little during the day, or in summer,
and can cool but little during the night, or in winter.
They, and the air over them, are therefore conserva-
tive as regards their temperatures. Land areas, and
the air over the lands, on the other hand, warm and
cool readily. The influence of latitude, as seen in
solar climate, is not infrequently wholly overcome by
the influence of land and water.
Marine or Oceanic Climate. Conservatism in its
temperature conditions is the most distinctive feature
of a marine climate. The results of the Chatten-
ger Expedition show that the diurnal range of air
temperature over the ocean between latitudes 0° and
40° averages only 2° or 8°. Further, the slow
changes in temperature of the ocean waters involve
a retardation in the times of occurrence of the maxima
and minima, and a marine climate, therefore, has
characteristically a cold spring and a warm autumn,
the seasonal changes of temperature being but slight.
The surface waters of oceans and lakes average some-
what warmer than the air over them, and for this
reason all considerable bodies of water which remain
unfrozen in winter become sources of warmth for the
adjacent lands during the colder months. Character-
istic, also, of marine climates is a prevailingly higher
38
CLIMATE
\
relative humidity, a larger amount of cloudiness, and
a heavier rainfall than is found over Continental inter-
iors. All of these features have their explanation in
the abundant evaporation from the ocean surfaces.
In the middle latitudes, again, there is this contrast
between the oceans and the Continental interiors, that
the former have distinctly rainy winters, while over
the latter the colder months have a minimum of pre-
cipitation. Ocean air is cleaner and purer than land
air, and ocean air is, on the whole, in more active mo-
tion, because friction of air on water is less than
friction of air on land.
It is obvious that an equable, damp, and cloudy
climate, such as that which is, on the whole, typical of
the oceans and of their leeward coasts, must affect
vegetation in a way quite different from that notecl
in a hotter and drier climate, with greater variations
of temperature. Thus Schindler has shown that
wheat contains less protein in a marine climate, and
hence more meat, leguminous plants, and other nitro-
genous foods are necessarily eaten. An interior
climate, like that of Southern Russia and Hungary,
produces wheat which is richer in protein; the need of
other nitrogenous foods is consequently decreased.
The proportion of starch is decreased, and that of
gluten is increased, in a hot, dry climate. The size
of the erop is also affected by the climate.
Continental Climate. Marine climate is equable;
Continental, is severe. The annual temperature
ranges increase, as a whole, with increasing distance
THE CLASSIFICATION OF CLIMATES
39
from the ocean; the regular diurnal ranges are also
large, reaching 85° or 40°, and even more, in the arid
J. F. M. A. M. J. J. A. S. 0. N. D. J.
Fig. 7. Influence of Land and Water on the
Annual March of Air Temperature
Continental interiors. The coldest and warmest
months are usually January and July, the times of
40
CLIMATE
maximum and minimum temperatures being less re-
tarded than in the case of marine climates. April is
usually warmer than October, unless spring warm-
ing is delayed by the melting of a snow-cover. In
the latter case, the snow-covered land surface tem-
porarily takes on the characteristics of a water
surface, and has a retarded spring. The greater sea-
sonal contrasts in temperature over the continents
than over the oceans are furthered by the less cloudi-
ness over the former. The clearer Continental skies
of high latitudes favour a lowering of the winter, but
a slight rise of the summer temperatures, while in
lower latitudes the clearer summer skies favour a
higher mean annual temperature. Diurnal and an-
nual changes of nearly all the elements of climate are
greater over continents than over oceans; and this
holds true of irregular, as well as of regular, varia-
tions. The contrast between marine and Continental
climates in the matter of the annual march of tem-
perature is shown in Figure 7. In low latitudes, the
curve for Funchal, on the island of Madeira (M),
represents the marine type, and that for Bagdad, in
Asia Minor (Bd), the Continental. For higher lati-
tudes, the curves for Valentia (V), a coast station
in the south-west of Ireland, and for Nerchinsk (N),
in eastern Siberia, are representatives of the two
types.
Owing to the distance from the chief source of
supply of water-vapour—the oceans—the air over
the larger land areas is naturally drier and dustier
THE CLASSIFICATION OF CLIMATES
41
than that over the oceans. Yet even in the arid Con-
tinental interiors in summer, the absolute vapour con-
tent is surprisingly large, although the air is still far
from being saturated. In the hottest months the
percentages of relative humidity may reach 20% or
30%. At the low temperatures which prevail in the
winter of the higher latitudes, the absolute humidity
is very low, but, owing to the cold, the air is often
damp. Cloudiness, as a rule, decreases inland, reach-
ing its minimum in deserts. And with this lower
relative humidity, more abundant sunshine and higher
temperature, the evaporating power of a Continental
climate is much greater than that of the more humid,
cloudier, and cooler marine climate. Actual evapo-
ration is, however, under these conditions, usually
much less than the possible evaporation which would
take place were there more water present to be
evaporated. Both amount and frequency of rain-
fall, as a rule, decrease inland, but the conditions are
very largely controlled by local topography and by
the prevailing winds. The decreased frequency of
rainfall on the lowlands is especially marked in win-
ter. Winds average somewhat lower in velocity,
and calms are more frequent, over continents than
over oceans. The seasonal changes of pressure over
the former give rise to systems of inflowing and out-
flowing, so-called Continental, winds, sometimes so
well developed as to become true monsoons. Usu-
ally, however, the changes in direction and the de-
velopment are not very marked.
42
CLIMATE
In winter, clear, crisp days, which are followed by
cold, calm nights, and interrupted from time to time
by spells of cloudy, windy weather, with or without
light precipitation; in summer, clear, calm nights,
followed by hot days with increasing wind velodty
and heavy clouds towards noon, and often by thun-
derstorms later in the aftemoon—these are typical
weather conditions of Continental interiors in the
higher latitudes; and they are of much interest to
man. The extreme temperature changes which oc-
cur over the continents are the more easily bome be-
cause of the dryness of the air; because the minimum
temperatures of winter occur when there is little or
no wind, and because, during the warmer hours of the
summer, there is the most air movement.
Desert Climate. An extreme type of Continental
climate may be found in deserts. It is a curious fact
that desert and marine climates—the two extremes of
the climatic scale—resemble one another in some re-
spects. Desert air, though often dusty by day, is
notably free from micro-organisms; the purity of
ocean air is well known. Again, deserts and oceans
alike have high wind velocities. The large diurnal
temperature ranges of inland regions, which are
most marked where there is little or no vegetation,
give rise to active convectional currents during
the warmer hours of the day. Hence high winds,
disagreeable because of the dust and sand which they
carry, are common by day, while the nights are apt
to be calm and relatively cool. Travelling by day is
THE CLASSIFICATION OF CLIMATES 43
unpleasant under such conditions. Diurnal cumu-
lus clouds, often absent because of the excessive dry-
ness of the air, are thus replaced by clouds of blowing
dust and sand. This sand, often carried afar, may
find a resting-place on the moister lands to leeward.
Thus beds of loess are formed. Indeed, many geo-
logical phenomena, and special physiographic types
of varied kinds, are associated with the peculiar con-
ditions of desert climate. The excessive diurnal
ranges of temperature cause rocks to split and break
up. Wind-driven sand erodes and polishes the rocks.
When the separate fragments become small enough,
they, in their turn, are transported by the winds and
further eroded by friction during their joumey. The
ground is often swept clean by the winds. Curious
conditions of drainage result from the deficiency in
rainfall. Rivers “ wither ” away, or end in sinks or
brackish lakes. Desert plants protect themselves
against the attacks of animals by means of thorns,
and against evaporation by means of hard surfaces
and an absence of leaves. The life of man in the des-
ert is likewise strikingly controlled by the climatic
peculiarities of strong sunshine, of heat, and of dust.
Occasionally heavy downpours of rain (cloud-bursts)
over mountains or on the borders of deserts, cause
sudden floods. Even slight rainfalls in deserts
awaken multitudes of dormant plant seeds.
Coast or Littoral Climate. Between the pure
marine and the pure Continental types, the coasts fur-
iysh almost every grade of transition. Hence coast
u
CLIMATE
or littoral climates may well be placed in a group by
themselves. Prevailing winds are here important
Controls. When these blow from the ocean, as on the
western coasts of the temperate zones, the climates
are more marine in character; but when they are off-
shore, as on the eastern coasts of these same zones, a
somewhat modified type of Continental climate pre-
vails, even up to the immediate sea-coast. Hence the
former have a much smaller range of temperature;
their summers are more moderate and their winters
milder; extreme temperatures are very rare; the air
is damp; there is much cloud. All these marine feat-
ures diminish with increasing distance from the ocean,
especially when there are mountain ranges near the
coast, as is the case in the western United States and
in Scandinavia. In the tropics, windward coasts are
usually well supplied with rainfall, and the tempera-
tures are modified by sea breezes. Leeward coasts
in the trade wind beits offer special conditions. Here
the deserts often reach the sea, as on the western coasts
of South America, Africa, and Australia. Cold ocean
currents, with prevailing winds along shore rather
than onshore, are here hostile to rainfall, although
the lower air is often damp, and fog and cloud are
not uncommon.
Monsoon Climate. Exceptions to the general rule
of rainier eastern coasts in trade wind latitudes are
found in the monsoon regions, as in India, for ex-
ample, where the western coast of the peninsula is
abundantly watered by the wet south-west monsoon.
THE CLASSIFICATION OF CLIMATES
46
As monsoons often sweep over large districts, not
only coast but interior, a separate group of monsoon
climates is desirable. In India, there are really three
seasons—one cold, during the winter monsoon; one
hot, in the transition season; and one wet, during the
summer monsoon. Little precipitation occurs in
winter, and that chiefly in the northern provinces.
The high temperatures of the transition periods are
most oppressive when the air is most damp. In India
this is the case in the autumn. In low latitudes, mon-
soon and non-monsoon climates differ hut little, for
summer monsoons and regular trade winds both give
rains, and wind direction has slight effect upon
temperature.
The winter monsoon is offshore, and the summer
monsoon onshore, under typical conditions, as in
India. But exceptional cases are found where the
opposite is true. Thus, on the north-westem coast of
Japan, the north-eastern coasts of Formosa and of the
Philippines, and the eastern coasts of the Southern
Deccan and of Ceylon, the prevailing offshore, winter,
dry monsoon becomes an onshore, rainy wind. Many
complicated cases of this kind are not easily co-ordi-
nated. In higher latitudes, the seasonal changes of
the winds, although not truly monsoonal, involve dif-
ferences in temperature and in other climatic de-
ments. The eastern coast of the United States has
prevailing cold, dry, clear winds from the Continental
interior in winter, while the prevailing winds of sum-
mer are south-west, and hence warm and often moist.
46
-
CLIMATE
The only well-developed monsoons on the coast of the
continents of higher latitudes are those of eastern
Asia. These are offshore during the winter, giving
dry, clear, and cold weather; while the onshore move-
ment in summer gives cool, damp, and cloudy
weather. Without these seasonal winds the winters
would have the maximum amount of rain and cloud.
Mountain and Plateau Climate. Both by reason
of their actual height and because of their obstructive
effects, mountains influence climate similarly in all
the zones. Hence mountain and plateau climates
are placed in a group by themselves, as distinguished
from those of lowlands. The former, as contrasted
with the latter, are characterised by a decrease in
pressure, temperature, and absolute humidity; an in-
creased intensity of insolation and radiation; larger
ranges in soil temperature; usually a greater fre-
quency of percipitation, and, up to a certain altitude,
more of it.
At an altitude of 16,000 ft., more or less, pressure
is reduced to about one-half of its sea-level value.
The highest human habitations are found under these
conditions. While the pressures and the pressure
changes at sea-level have no marked effect upon man,
the physiological effects of the decreased pressure
aloft (faintness, nausea, headache, weakness) are ex-
perienced by a majority of people at altitudes above
12,000 to 15,000 ft. The symptoms, and the height
at which they appear, vary much in different cases,
and depend upon the physical condition of the indi-
THE CLASSIFICATION OF CLIMATES
47
vidual, the weather, bodily exertion, and so on. The
greatest altitudes attained by man were reached by
balloon, and in such cases a supply of oxygen is usu-
ally taken up by the aëronaut. Man endures the
rapid pressure changes during balloon ascents with
difficulty, and often only with considerable suffering.
The eagle and the condor, however, suffer no incon-
venience during their high flights.
It has been suggested by Jourdanet that mountain
and plateau climates be divided into groups, climats
de montagne, below 6500 feet, and climats d’altitude,
above that height. The former are beneficial because
of the stimulating quality of their clean, cool air; the
latter may be injurious because of the low pressure.
The variations in pressure, as well as the actual press-
ures, diminish aloft. On high mountains and plat-
eaus, the pressure is lower in winter than in summer,
owing to the fact that the atmosphere is compressed
by cold to lower levels in the winter, and is exp&nded
upwards in summer by heat. The morning minimum
pressure on mountains is usually the primary mini-
mum, the aftemoon minimum being less marked and
coming later than on lowlands. Figure 8 shows the
diurnal variation of pressure at Geneva (408 meters,
G), Beme (578 meters, B), on the Santis (2467
meters, S), and on the summit of Mont Blanc (4811
meters, MB), and illustrates well the general char-
acteristics of the curves found at different altitudes.
Local topography, however, is an important control-
ling influence, and modifies such curves very much.
48
CLIMATE
The intensity of insolation and of radiation both
increase aloft in the cleaner, purer, drier, and thinner
air of mountain climates. The sun usually shines more
often and more powerfully at high altitudes. The
0!* 4t> 8t> NOON I6(? 2011 24*!
Fig. 8. Diurnal Variation of Pressure : Influence of Altitude
intensity of the sun’s rays attracts the attention of
mountain-climbers at great altitudes. The excess of
surface temperature over air temperature also in-
creases aloft, and is a favourable element in plant
growth. There is likewise an increase in the range of
surface temperature, although this is much influenced
THE C LAESIE WAT ION OF CLIUATEE 49
by exposure. The vertical decrease of temperature,
which is also much affected by local conditions, is es-
pecially rapid during the warmer months and hours;
mountains are then cooler than lowlands. The in-
versions of temperature characteristic of the colder
months, and of the night, give mountains the advan-
tage of higher temperature then, a fact of importance
in connection with the use of mountains as winter re-
sorts. At such times, the cold air flows down the
mountain sides and collects in the valleys below, be-
ing replaced hy warmer air aloft. Hence diurnal
and annual ranges of temperature on the mountain
tops of middle and higher latitudes are lessened, and
the climate in this respect resembles a marine condi-
tion; but topography and the conditions of local
clouds and winds are here important Controls. The
times of occurrence of the maximum and minimum
are also much influenced by local conditions. Figure
9 shows the diurnal march of temperature for Paris
(solid) and the Eiffel Tower (broken) in January
and July. It will be noted that the times of maxi-
mum and minimum are retarded on the Eiffel Tower,
and that the range is less than at the earth’s surface.
These are characteristics of mountain climates. Ele-
vated, well-endosed valleys, with strong sunshine,
often resemble Continental conditions of large tem-
perature range; and plateaus, as compared with
mountains at the same altitude, have relatively higher
temperatures and larger temperature ranges. Alti-
tude tempers the heat of the low latitudes. High
50
CLIMATE
mountain peaks, even on the equator, can remain
snow-covered the year around; the plateau of south-
Fig. 9. Diurnal Variation of Temperature : Influence of
Altitude
em India, at 6000 to 7000 ft. above sea-level, always
has moderate mean temperature, and from the dense
THE CLASSIFICATION OF CLIMATES
51
jungle of the tropical lowland to the snowy moun-
tain top, successive zones of vegetation are en-
countered.
Nine-tenths of the water vapour in the atmosphere
are below 21,000 feet. Hence mountains are im-
portant vapour barriers, and one side may be damp
while the other is dry. Curiously mistaken ideas of
distance often result from the remarkable clearness
and dryness of the air on high mountains. No gen-
eral law govems the variations of relative humidity
with altitude, but on the mountains of Europe the
winter is the driest season, and the summer the
dampest. At well-exposed stations there is a rapid
increase in the vapour content soon after noon, espe-
cially in summer. The same is true of cloudiness,
which is often greater on mountains than at lower
levels, and is usually at a maximum in summer, while
the opposite is true of the lowlands in the temperate
latitudes. One of the great advantages of the higher
Alpine valleys in winter is their small amount of
cloud. This, combined with their low wind velocity
and strong insolation, makes them desirable winter
health resorts. Latitude, altitude, topography, and
winds are determining factors in controlling the
cloudiness on mountains. In intermediate latitudes
there is a seasonal migration of the level of maximum
cloudiness, and of maximum relative humidity, from
the lowlands in winter to higher altitudes in the
warmer months, in association with the diurnal con-
vectional movements of the warmer season. Frequent
52
CLIMATE
rapid local changes also occur. In the rare, often
dry, air of mountains and plateaus, evaporation is
rapid, the skin dries and cracks, and thirst is increased.
Rainfall usually increases with increasing altitude
up to a certain point, beyond which, owing to the loss
of water vapour, this increase stops. The zone of
maximum rainfall averages about 6000 to 7000 feet
in altitude, more or less, in intermediate latitudes,
being lower in winter and higher in summer. Moun-
tains usually have a rainy and a drier side; the con-
trast between the two is greatest when a prevailing
damp wind crosses the mountain, or when one slope
faces seaward and the other landward. When the
prevailing winds differ little in dampness, this con-
trast is lessened, and there may then be a very close
corréspondence between the rainfall and the topo-
graphic map of a region. Mountains often provoke
rainfall, and local “ islands,” or, better, “ lakes,” of
heavier precipitation result. Such are found on the
mountains of the Sahara, and of other deserts. This
local precipitation favours the growth of vegetation;
small streams and oases are found, and temporary
camps, or more permanent settlements, of the no-
madic tribes of the desert are there established. Well-
marked zones of vegetation are noted under such
conditions, as in the transition from the dry Califor-
nian lowlands up through the deciduous, and then the
coniferous, forests of the Siërra Nevada to the snows
on the summits. Similarly, the high plateaus of
southem Utah and of Arizona are high enough to re-
THE CLASSIFICATION OF CLIMATES
53
ceive fairly abundant rainfall, while the lowlands are
arid.
Mountains resemble marine climates in having
higher wind velocities than Continental lowlands;
mountain summits have a noctumal maximum of
wind velodty, while plateaus usually have a diurnal
maximum. Mountains both modify the general, and
give rise to local, winds. Among the latter, the well-
known mountain and valley winds are often of con-
siderable hygienic importance in their control of the
diurnal period of humidity, cloudiness, and rainfall,
the ascending wind of daytime tending to give clouds
and rain aloft, while the opposite conditions prevail
at night. The high temperature and dryness of the
foehn, which is of immense benefit to man by reason
of its melting and evaporating powers, although of-
ten enervating and depressing, result from the fact of
a descent of the air from a mountain slope or summit.
The bora, with its cold gust, is a wind in whose de-
velopment a mountain or plateau is essential. And
the mistral of Southern France owes some of its cold
to radiation over the interior plateaus.
Mountains as Climatic Divides. Very different
conditions of temperature, pressure, and humidity
may be found on the opposite sides of a well-defined
mountain range, because such a range interferes with
the free horizontal interchange of the lower air.
Mountain ranges which trend east and west, like the
Alps and the Himalayas, separate more severe from
less severe climates; those which follow a coast-line, as
54
CLIMATE
in California, Scandinavia, or eastern Siberia, separ-
ate marine from Continental. Large differences of
pressure on the two sides may be equalised by a flow
of air across the mountain, as in the foehn.
CHAPTER III
THE CLASSIFICATION OF CLIMATES (Continued)
Supan’s Climatic Provinces—Köppen’s Classification of Climates—
Raven stein’s Hygrothermal Types—Classification of Rainfall
Systems—Herbertson’s Natural Geographical Regions—Sum-
mary and Condusions.
Supan’s Climatic Provinces. The ordinary classi-
fication into Continental, marine, and mountain cli-
mates is too general. Some scheme of classification is
needed in which the geographical factor plays an im-
portant part, and which recognises the types of
climate, possessing common characteristics of tem-
perature, rainfall, and winds, that occur over areas
having similar topographic conditions. A fairly sim-
ple scheme of this kind has been suggested by Supan,
who recognises thirty-five so-called climatic prov-
inces, but any such rigid subdivision is obviously sus-
ceptible of almost infinite modification. Twenty-one
of these provinces are in the eastern hemisphere, in-
cluding Polynesia; twelve are in the western, and
two in the polar zones. The description of thesk
provinces is as follows:1
1. Arctic Province. This coincides with the
i Free translation of original, following Bartholomew's Atlas of
Meteorology, p. 7.
55
56
CLIMATE
north polar cold cap, the area wherein the mean tem-
perature of the warmest summer month is never over
50° F., and within which trees do not grow.
2. West European Province. Mild winters, ow-
ing to influence of the westerly winds and Gulf
Stream. Yearly temperature range under 59° F.
Fig. io. Supan’s Climatic Provinces
(15° C.). Plentiful rainfall, fairly well distributed
throughout the year, but varying in quantity owing
to great diversity of land contours. The climatic
conditions often vary in short distances, and hence the
region can be divided into many subdivisions.
3. East European Province. Here the evidences
of a land climate begin to be observed; but as most of
the region is a plain, differences depend mainly on
latitude. The rainfall is smaller than in Province 2,
CLASSIFICATION OF CLIMATES
57
and gradually diminishes towards the southeast, and
has a marked summer maximum.
4. West Siberian Province. This is separated
from 8 by the limit of the positive annual isanomal-
ous lines, which practically coincide with the Urals.
The characteristic peculiarities of 8 are found here
greatly emphasised, and the greater variability of
temperature is to be noted.
5. East Siberian Province. A gradual rising of
the ground is found east of the Yenisei, with low
plains only along the rivers. The winter cold pole
is here, and thé yearly range of temperature is a
maximum. As a rule, the rainfall is small.
6. Kamchatkan Province. The sea diminishes
the temperature extremes noted in Province 5, and
much rain falls.
7. Sino-Japanese Province. On the continent,
relatively well-marked winter cold, and strong peri-
odical rains. In Japan, these peculiarities are less
extreme.
8. Asiatic Mountain and Plateau Province.
This includes all the lofty plateaus bounded by
mountain ranges, which shield it on every side, and
so render it very dry. The great height makes the
winter temperature severe; but the summer heat is
great, owing to the Continental position. The daily,
as well as the yearly, range of temperature is very
marked.
9. Aral Province. Dry, low-lying plain, with the
greatest rainfall in the north in summer, and in the
58
CLIMATE
south in winter. The plains of western Turkestan
have severe winters and very hot summers.
10. Indus Province. A plain remarkable for
great dryness and heat.
11. Mediterranean Province. Very varied in
climate, owing to its great irregularity of outline,
both horizontal and vertical. Mild, except on high
plateaus. Winter rains.
12. Saharan Province. Reaches to Mesopota-
mia. Region of dry, north winds, and probably the
one receiving least rain. Its Continental position and
lack of vegetation increase the heat of summer ex-
traordinarily; both annual and daily ranges of tem-
perature are considerable.
18. Tropical African Province. Owing to the
height of the central plateau, the heat is less intense,
but it is very great on the narrow Coastal plains.
Tropical rains decreasing towards the jvest.
14. Kalahari Province. Includes all the almost
rainless region of Southwest Africa.
15. Cape Province. Sub-tropical.
16. Indo-Australian Monsoon Province. Strong,
periodical rains are brought with the Southwest and
northwest monsoons, except at a few places in the
ardhipelago. The temperature is fairly uniform,
despite the great extent of the province, and the
yearly range is very small.
17. Inner Australian Province. With great ex-
tremes of temperature. Irregular and rare rains.
18. Southwest Australian Province. Sub-tropical.
CLASSIFICATION OF CLIMATES
59
19. East Australian Province. It extends to the
water-parting and includes the southeast coast and
Tasmania. Plentiful and fairly regular rains. Mod-
erate range of temperature.
20. New Zealand Province. Probably includes
the small neighbouring islands. Mild climate, with
fairly regular rains.
21. Tropical Polynesian Province. Tropical cli-
mate, ameliorated by the ocean, so that mild sum-
mer weather prevails throughout the year. On the
loftier islands, the rain is abundant, and has a tropi-
cal periodicity.
22. Hawaiian Province. Also a mild climate,
but with sub-tropical rains.
28. Hudson (North Canadian) Province. Great
extremes of temperature and little precipitation.
24. Northwest American Coastal Province. Mild,
equable, rainy climate.
25. Californian Province. Relatively cool, es-
pecially in summer. Marked sub-tropical rainy
seasons.
26. North American Mountain and Plateau
Province. Great yearly and daily ranges. Dry.
27. Atlantic (East North American) Province.
Great contrast in temperature conditions of north
and south in winter. Extreme climate even on the
coast. Plentiful rains, evenly distributed through-
out the year. Great variability.
28. West Indian Province. This also includes
the soulhem rim of North America. Equable tem-
60
CLIMATE
perature. Rain at all seasons, but with a marked
summer maximum.
29. Tropical Cordilleran Province. On the in-
terior plateau, perpetual spring, owing to consider-
able height above sea-level. In Mexico and Central
America, marked zenithal rains; in South America,
more regular precipitation.
80. South American Tropical Province. Little
that is certain is known about this province, which in-
cludes mountainous regions and plains, and ought,
therefore, to possess considerable variety of climate.
81. Peruvian Province. This province extends
as far south as 80° S., and so includes the northem
part of Chile. Abnormally cool. Rainless.
82. North Chilean Province. Sub-tropical.
88. South Chilean Province. Equable tempera-
tures, with cool summers. Extraordinarily rainy.
84. Pampa Province. Range of temperature
fairly large, especially in the north. Rain not
plentiful.
35. Antarctic Province. Resembles the Arctic, so
far as can at present be determined, in winter cold
but differs in having a very low summer temperature
and a very regular distribution of pressure and winds.
Fig. 10 shows the geographical distribution of
these climatic provinces.
Köppen’s Classification of Climates. An interest-
ing classification of climates, from a botanical stand-
point, is that proposed by Koppen. This rests upon
certain critical values of the temperature and rain-
CLASSIFICATION OF CLIMATES
61
fall of the warmest or coldest, or of the wettest and
driest month. The plant classification proposed by
A. de Candolle in 1874, and later adopted by Drude,
is accepted. This is a division into five principal
biological groups under the control of temperature
and moisture, as follows:
A. Megatherms: plants which need continuously
high temperature without much annual range, and
also abundant moisture. There is no cool season; the
temperature of the coolest month is over 64.5°
(18° C.), and there is at least one month of heavy rain.
When there are marked dry seasons, the principal one
comes in winter and spring. In parts of this belt
there are two rainy seasons. In this belt are found
the lofty tropical forests intertwined with vines and
creepers—sago, betel, pepper, cacao, bread-fruit,
baobab, coffee, sugar-cane, banana, ginger, and so on.
B. Xerophytes: plants which like dryness and .
need high temperatures, at least for a short season.
These are found in tropical districts which have a
long dry season, and in the steppes and deserts of the
tropics and of the warmer parts of the temperate
zones. They are adapted in various ways for life in
a dry climate; they rest during the dry time, and, in
extreme cases, where rain may not fall for years, they
survive as seeds. The vegetation varies with the soil.
In this group we find the date, mesquite, acacia, cac-
tus, agave, and similar plants.
C. Mesoiherms: need moderate heat (59°-68°)
and a moderate amount of moisture; some require
62
-
CLIMATE
high summer temperatures; others shun low win-
ter temperatures; others shun the dryness which of-
ten accompanies high summer temperatures. These
plants inhabit latitudes between 22° and 45° N. or
40° S., so long as the moisture continues sufficiënt.
There is a cool season—coldest month below 64.5°
(18° C.)—and a hot summer—warmest month over
72° (22° C.),—or a mild winter—coldest month over
48° (6° C.)—or both. The classic Mediterranean
climate is found in this belt. The mesotherm belt
jcontains the tea, maté, rice, cotton, magnolia, hickoiy,
arbor vit®, hemlock, wheat, com, olive, fig, grape,
heath, cinchona, etc.
D. Mikrotherm.8: need less heat, lower mean an-
nual temperature, cooler and shorter summers, and
colder winters. The warmest month is at least 50°
(10° C.) and not over 72° (22° C.); the coldest is be-
low 48° (6° C.), with at least an occasional snow-
cover in winter and sufficiënt rainfall in the warmer
season. Evergreen and deciduous forests, grains,
and, in the warmer portions, fruit and corn are found.
E. Heki8totherm8: plants of the Arctic zone, be-
yond the limits of tree growth and of the zone of
scrubby Antarctic vegetation. These need the least
heat. Mosses, lichens, and similar lowly forms are
typical.
A simple scheme of distribution of these five groups
of plants may first be developed with reference to an
ideal continent, stretching from pole to pole, with
oceans on both sides and without mountains (Fig.
CLASSIFICATION OF CLIMATES
63
11). Here a a is the western and b b the eastern
coast. The approximate latitudes are given at the
margins. The groups of de Candolle’s System are
arranged as shown, if the xerophytes are limited to
Fig. ii. General Distribution op
Plant Zones
the deserts and steppes, and if those woody plants
of the megatherm and mesotherm zones which are
adapted to a dry climate are included within these
zones. The typical zonal arrangement is interrupted
in latitudes 20° to 50° by the fact that the arid dis-
64
CLIMATE
trict of the xerophytes (B) is wedged in on the west
coast between A and C. Farther east, zone B broad-
ens poleward, cuts through the middle of the meso-
therm zone, and usually ends without reaching the
east coast.
The five principal types are further subdivided un-
til the whole number of climates reaches twenty-four.
The special conditions which characterise each cli-
mate are carefully determined, and each sub-climate
is named after one of its characteristic plants or ani-
CLASSIFICATION OF CLIMATES
66
mals; or af ter some distinctive meteorological pheno-
menon; or, again, af ter the general character of its
vegetation. Fig 12 gives the limits of the different
Fig. 13. Na mes of Climates
at Sea-Level
sub-climates, and also the characteristic conditions of
temperature and precipitation.1 Fig. 18 gives the
1 Figures are degrees Fahr. C = coldest month. W = warmest
month. 4 M = 4 months. dr. 1.2 in. = driest month rainfall 1.2 in-
ches. D. 18° and D 36° = difference between extreme months
18° and 36°. q = quotiënt obtained by dividing the amount of
rainfall in the wettest month (in mm.) by the maximum vapour'
tension (in mm.) at the mean temperature of the same month, an
5
66
CLIMATE
scheme of the sub-climates for the lowlands, with their
names. Four climates which do not occur at sea-
leve! are here lacking (C7, E8, E4, F)The verti-
Alti- tude m. 4000 Vertical Diatrfb Continental lype Alti- tude m.
9000 4000
9000 ic*-« e 9000
1000 I 9000
ÏOOO
Fïo. 14. Vertical Distribution op Climates
cal distribution of these climates, much simplified, is
shown in Fig 14. The descent of the climatic strata
from equator to higher latitudes is shown on the right
for the Continental, and on the left for the marine type,
as far as about latitude 57°. Climates Cl to C4,
and Dl and D2, have large temperature ranges, and
are therefore lacking at the equator and on the ocean;
while C5 to C7, and D3, have small ranges, and are
not found on the continents in higher latitudes. The
general control of pressure, winds, and ocean currents
over the climatic types is shown in the two following
ideal diagrams, in which the two vertical lines indi-
cate the west and east coasts of the ideal continent,
and the area included reaches to the middle of the ad- * 1
expression which combines the effect of rainfall and evaporating
power. r=rain probability of rainiest month.
1C7, High savanna climate; E3, Yak, or Pamir climate; E4,
Chamois or high alpine climate; F, perpetual frost, without life.
CLASSIFICATION OF CLIMATES
67
jacent ideal oceans. The line 0°-0° is the equator
(Figs. 15 and 16). The short arrows give the wind
direction 500-1000 metres above the surface; calms
are represented by the sign o ; the long broken arrows
Fig. 15. Prbssurb and Winds in January
indicate the prevailing surface ocean currents. At a a
there is a rise of cold water from beneath the surface
of the ocean. The curving lines are sea-level isobars;
the lower pressures are shaded. The letters and
68
CLIMATE
boundaries, drawn in short, slanting lines in Fig. 16
indicate the climatic districts of Fig. 11. Fig. 15 is
similar to Fig. 16, as far as these climatic districts are
Fig. 16. Pressure and Winds in July
concemed. Therefore the letters and boundaries
are omitted. Fig. 17 shows the geographical distri-
bution of the climatic types and sub-types.
Ravenstein’s Hygrothermal Types. Recognising
69
Fig. 17. Köppen’s Classification of Climates in Relation to Vegetation
70
CLIMATE
the importance of relative humidity as a climatic
factor in its influence upon life, upon agriculture and
upon industry, and basing his grouping of climates
upon certain relations between temperature and rela-
tive humidity, Ravenstein proposes a subdivision of
the earth’s surface into sixteen hygrothermal climatic
types. The general characteristics and examples of
these types are as foiïows:
1. Hot (73° and over) and very damp (humidity
81% or more): Batavia, Cameroons, Mombasa.
2. Hot and moderately damp (66-80%): Ha-
vana, Calcutta.
8. Hot and dry (51-65%): Bagdad, Lahore,
Khartum.
4. Hot and very dry (50% or less): Disa, Wadi
Halfa, Kuka.
5. Warm (58° to 72°) and very damp: Walfish
Bay, Arica.
6. Warm and moderately damp: Lisbon, Rome,
Damascus, Tokio, New Orleans.
7. Warm and dry: Cairo, Algiers, Kimberley.
8. Warm and very dry: Mexico, Teheran.
9. Cool (88° to 57°) and very damp: Greenwich,
Cochabamba.
10. Coól and moderately damp: Vienna, Mel-
boume, Toronto, Chicago.
11. Cool and dry: Tashkent, Simla, Cheyenne.
12. Cool and very dry: Yarkand, Denver.
18. Cold (32° or less) and very damp: Ben Nevis,
Sagastyr, Godthaab.
CLASSIFICATION OF CLIMATES
71
14. Cold and moderately damp: Tomsk, Pike’s
Peak, Polaris House.
15. Cold and dry: (No example given).
16. Cold and very dry: Pamir.
Classification of Rainfall Systems.—The seasonal
occurrence of rainfall has suggested a classification
of the rainfall systems of the world into types. While
these schemes are useful in climatological study, they
are hardly to be considered as classifications of cli-
Fig. 18. Herbkrtson’s Major Natural Regions
mate. Mühry1 2 gave a rigid scheme of rainfall types
in six beits for each hemisphere, these beits being
divided by latitude lines; and Koppen has prepared
a useful map of the hyetal regions of the world, based
on the seasonal distribution of rainfall types.3
1A. Mühry: Klimatographische Uebersicht der Erde, Leipzig
and Hfeidelberg, 1862, 741-744. Also: AUgemeine geographische
Meteorologie, 1860, 145, and note 28, 199. Containing chart, as
well as the scheme of rainfall types.
2 See Atlas of Meteorology, Plate 19.
72
CLIMATE
Herbert8orÏ8 Natural Geographical Region*.—A
scheme of “ natural geographical regions ” has been
suggested by Herbertson,1 the basis of classifica-
tion being a certain unity of temperature, rainfall
seasons, configuration and vegetation (Fig. 18).
The different types of natural regions recur in
fairly systematic order on the different continents,
being chiefly controlled by marine and Continental in-
fiuences, and each type, wherever found, has certain
similar general relations to human life and develop-
ment, as well as to animals and plants. The types
are as follows:
1. Polar. (a) Lowlands (Tundra type); (b)
Highlands (Ice-cap type).
2. The cool temperate regions. (a) Western
margin (West European type); (b) Eastern mar-
gin (Quebec type); (c) Interior lowlands (Siberian
type); (d) Interior mountain area (Altai type).
8. The warm temperate regions. (o) Western
margin with winter rains (Mediterranean type);
(b). The eastern margin, with summer rains (China
type); (c) The interior lowlands (Turan type); (d)
Plateau (Iran type).
4. (a) The west tropical deserts (Sahara type);
(b) East tropical lands (Monsoon type); (c) Inter-
tropical table-lands (Sudan type).
1 A. J. Herbertson: “ The Major Natural Regions: An Essay in
Systematic Geography.” Geogr. Joum. xxv., 1965, 300-309. A
revised chart has been published in Herbertson’s The Senior
Geography, Oxford, 1907. (The Oxford Geographies, Vol. III.)
CLASSIFICATION OF CLIMATES
73
5. Lofty tropical or sub-tropical mountains (Tib-
etan type).
6. Equatorial lowlands (Amazon type).
Summary and Conchmom. The broad classifica-
tion of climates into the three general groups of
marine, Continental, and mountain, with the subor-
dinate divisions of desert, littoral, and monsoon, is
convenient for purposes of summarising the interac-
tion of the climatic elements under the Controls of
land, water, and altitude. But in any detailed study,
some scheme of classification is needed in which simi-
lar climates in different parts of the world are
grouped together, and in which their geographic dis-
tribution receives particular consideration. It is ob-
vious from the preceding paragraphs that an almost
infinite number of classifications might be proposed;
for we may take as the basis of subdivision either the
special conditions of one climatic element, as, for ex-
ample, the same mean annual temperature, or mean
annual range of temperature, or the same rainfall, or
rainy seasons, or humidity, and so on. Or again,
similar conditions of the combination of two or more
elements of climate may be made the basis of classifi-
cation. Or we may take a botanical, or a zoölogical
basis. Of the classifications which have been pro-
posed, special reference is here made to those of
Supan, Koppen, and Herbertson. That of Supan,
taken as a whole, gives a rational, simple, and satis-
factory scheme of grouping, whose frequent use in
climatic descriptions would tend toward system, sim-
74
CLIMATE
plicity, and facility of comparison. It emphasises
the essentials of each climate, and serves to impress
these essentials upon the mind by means of the com-
pact, well-considered summary which is given in the
case of each province described. Obviously, no clas-
sification of climates which is at all complete can ap-
proach the simplicity of the ordinary classification of
the zones.
Köppen’s admirable scheme of subdividing climates,
with the emphasis on the botanical side, is perhaps
better adapted to the use of students of plant geogra-
phy than of general climatology. But it has the
great merit of recognising the existing differences of
climate between east and west coasts, and between
coasts and interiors. The co-ordination of districts
of vegetation and of climate, which this scheme so
strikingly emphasises, is a noteworthy fact in clima-
tology. The subdivision could obviously be continued
almost indefinitely.
Herbertson’s classification of the natural geo-
graphical regions is, on the whole, not very unlike that
adopted in Supan’s climatic provinces, but is less com-
plete. It is obvious that no scheme of subdivision
of this kind can be regarded as being rigid or as sat-
isfying all students of questions of distribution.
Nevertheless, some general grouping of climatic re-
gions with reference to similar features of tempera-
ture and rainfall and configuration, is a distinct help
in most geographical studies. The larger types
naturally recur on the several continents, in a fairly
CLASSIFICATION OF CLIMATES
75
systematic fashion. It results from this fact that
there is a recurrence, in a large way, of somewhat
similar conditions of life. This is a particularly help-
ful consideration in investigations of the economie
and political history of mankind. The chief pecul-
iarities of the important types can be readily leamed;
the special variations in individual areas may be in-
vestigated for each case by itself.
Ravenstein’s hygrothermal types rest upon unsatis-
factory data, and regions of very different climatic
conditions are grouped together because they happen
to have the same mean annual temperature and rela-
tive humidity.
CHAPTER IV
THE CHABACTERISTICS OF THE ZONES: I.—THE
TROPICS
General: Climate and Weather—Temperature—The Seasons—
Physiological Effects of Heat and Humidity—Pressure—Winds
and Rainfall—Land and Sea Breezes—Thunderstorms—Cloudi-
ness—Intensity of Skylight and Twilight—Climatic Subdivi-
sions:—I. The Equatorial Belt.—II. Trade Wind Beits.—III.
Monsoon Beits.—IV. Mountain Climate.
General: Climate and Weather. The so-called
“ torrid zone ” has been variously bounded. lts
limits have been set at the tropics (lat. 23^°); at the
mean annual isotherms of 68°, which also correspond
closely with the poleward extension of palms; and at
the polar margins of the trade winds. The dominant
characteristic of this great belt, embracing but a little
less than one-half of the earth’s surface, is the re-
markable simplicity and unifórmity of its climatic
features. This simplicity is reflected in the striking
regularity in the recurrence of the ordinary weather
phenomena. The tropics lack the proverbial uncer-
tainty and changeableness which characterise the
weather of the higher latitudes. In the torrid zone,
weather and climate are essentially synonymous
terms. Periodic phenomena, depending upon the
daily and annual march of the sun, are dominant.
Non-periodic weather changes are wholly subordi-
76
CHARAVTERISTICS OF ZONES—TROPICS 77
nate. The succession of daily weather changes is even
more regular, and the distribution of the climatic ele-
ments is even more uniform over the tropical oceans
than over the lands. In special regions only, and at
special seasons, is the regular sequence of weather
temporarily interrupted by an occasional tropical
cyclone. These cyclones, although comparatively in-
frequent, are notable features of the climate of the
areas in which they occur. Generally bringing very
heavy rains, and thus locally increasing the total an-
nual precipitation by a considerable amount, they yet
cause no marked temperature changes such as those
which are the common accompaniments of extra-
tropical cyclones. The devastation produced by one
of these storms often affects the economie condition
of the people in the district of its occurrence for many
years.
Temperature. The sun is always well up in the
sky. The length of day and night varies little.
Hence the mean temperature is high, it is very uni-
form over the whole zone, and there is little variation
during the year. The mean annual isotherm of 68°
is a rational limit at the polar margins of the zone,
and the mean annual isotherm of 80° encloses the
greater portion of the land areas, as well as much of
the tropicaK oceans. The isotherms are thus far
apart. The warmest latitude circle for the year is
not the equator, but latitude 10° north. The highest
mean annual temperatures, shown by the isotherm
of 85°, are in central Africa, in India, the north of
78
CLIMATE
Australia and Central America, but, with the excep-
tion of the first, these areas are small. Massowah, on
the Red Sea, has an annual mean of over 86°. The
temperatures average highest where there is little
rain, and not in the belt of heavy equatorial rains,
where the clouds afford some protection from the
sun’s rays. In June, July, and August there are
large districts in the south of Asia, and in northern
Africa, with temperatures over 90°. Winds blowing
out from these heated deserts are uncomfortably hot
and dusty.
Over nearly all of the zone the mean range of tem-
perature is less than 10°, and over much of it, especi-
ally the oceans, it is less than 5°. At Equatorville,
in the interior of Africa, on the Congo, the mean
annual range is only a little over 2°; at Iquitos (lat.
8.7° S.), in Peru, it is 4.8°* Even near the margins
of the zone, where the seasonal di ff erences are great-
est, the ranges are less than 25°, as at Calcutta, Hong
Kong, Rio de Janeiro and Khartum. The mean
daily range is usually larger than the mean annual.
Thus at Equatorville the former is about 14.5°. It
has been well said that “night is the winter of the
tropics.” The differences between the maximum and
minimum temperatures of the year near the equator
are not much greater than the daily range. Over an
area covering parts of the Pacific and Indian Oceans,
from Arabia to the Caroline Islands and from Zan-
zibar to New Guinea, as well as on the Guiana coast,
CHABACTERISTICS OF ZONES—TROPICS 79
the minimum temperatures do not normally fall be-
low 68°,. and over much of the torrid zone as a whole
they do not fall below 59°. Towards the margins of
the zone, however, the minima on the continents fall
to, or even below, 82°. Maxima of 115°, and even over
120° (122°), occur over the deserts of northern
Africa. A district where the mean maxima exceed
118° extends from the western Sahara to northwest-
ern India, and over central Australia. Near the
equator the maxima are therefore not as high as those
in many so-called “ temperate ” climates. The
greater portion of the torrid zone is a water surface,
and marine conditions are therefore typical for most
of it. These tropical oceans show remarkably small
variations in temperature. The ChaUenger re-
sults showed a daily range of hardly 0.7° in the sur-
face water temperature on the equator, and Schott de-
termined the annual range as 4.1° on the equator; 4.3°
at latitude 10°, and 6.5° at latitude 20°. It has been
clearly pointed out by Hann that the uniform dis-
tribution of temperature throughout the year—the
dominant feature of the tropics—results not only
from (1) the small variation in insolation and in the
length of the day; but also (2) from the great extent
of the zone, which makes it impossible for cold winds
from higher latitudes to penetrate into the lower lati-
tudes; (8) the oblique course of the trades, which are
well warmed on their indirect road towards the equa-
tor; (4) the slight noctumal cooling, where the air
80
-
CLIMATE
is damp and vapour is readily condensed; and (5) the
great extent of the tropical oceans, which gives so
much of the zone a marine climate.
The Seasons. In a true tropical climate, seasons,
in the temperate zone sense, do not exist. The varia-
tions in temperature throughout the yeai' are so slight
that the seasons are not classified according to tem-
perature, but depend on rainfall and the prevailing
winds. The life of animals and plants in the tropics,
and of man himself, is regulated very largely, in some
cases almost wholly, by rainfall. Agriculture pros-
pers, or fails, according to the sufficiency and punct-
ual appearance of the rains. After a long dry season,
when the rains come, there is an extraordinarily
sudden awakening of the parched and dusty vegeta-
tion. Where, on the other hand, there is abundant
moisture throughout the year, a tree may at the same
time be carrying buds, blossoms, and ripe fruit.
Vegetation under these conditions has been well called
non-periodic. Although the tropical rainy season is
characteristically associated with a vertical sun (i. e.,
summer), that season is not necessarily the hottest
time of the year. The temperature is usually some-
what lower under the clouds. The rainy season often
goes by the name of winter for this reason, and also
because the weather is dull. The time of the maxi-
mum temperature is also controlled by the rainy sea-
son. Towards the margins of the zone, with increas-
ing annual ranges of temperature, seasons in the ex-
tra-tropical sense gradually appear.
CHARACTERISTICS OF ZONES—TROPICS 81
Physiological Effects of .Heat and Humidity.
Tropical monotony of heat is associated with high
relative humidity, except over deserts and in dry sea-
sons. The air is therefore muggy and oppressive.
The high temperatures are disagreeable and hard to
bear. The “ hot-house air ” has an enervating effect.
Energetic physical and mental action are often diffi-
cult, or even impossible. The tonic effect of a cold
winter is lacking. The most humid districts in the
tropics are the least desirable for persons coming from
higher latitudes; the driest are the healthiest. The
most energetic natives are the desert-dwellers. The
monotonously enervating heat of the humid tropics
weakens, so that man becomes sensitive to slight tem-
perature changes. A fall of temperature to within
a few degrees of 70° seems to some tropical natives
almost unbearably cold, and certain African tribes
sleep on clay banks heated inside by fires, although
the mean temperature of the coldest month is over
70°. In drier climates such changes are more easily
home. The intensity of direct insolation, as well as
of radiation from the earth’s surface, may produce
sunstroke and heat prostration. “Beware of the
sun ” is a good rule in the tropics.
Pressure. The uniform temperature distribution
in the tropics involves uniform pressure distribution.
Pressure gradients are weak. The annual fluctuations
are slight, even on the continents. The diurnal varia-
tion of the barometer is so regular and so marked
that, as von Humboldt said, the time of day can be
82
CLIMATE
told withui about fifteen minutes if the reading of the
barometer be known. Even severe thunderstorms do
not overcome the regular diurnal march of the press-
ure, but the approach of tropical cyclones can be
foretold by the pressure changes.
Winds and Rainfall. Within the tropics, there are
both heavy rains and large districts of very deficiënt
precipitation. Along the barometric equator, where
the pressure gradients are weakest, is the equatorial
belt of calms, variable winds and rains—the dol-
drums. This belt, with its actively ascending, damp,
hot air, offers exceptionally favourable conditions for
abundant rainfall, and belongs among the rainiest
regions of the world, averaging probably about one
hundred inches. The rainfall is so heavy that the
salinity of the surface waters of the oceans is actu-
ally less than in the latitudes of the trades. The
sky is prevailingly cloudy, especially in the early
afternoon hours; the air is hot and oppressive; heavy
showers and thunderstorms are frequent, chiefly in
the afternoon and evening—conditions not very un-
like those which exist during certain spells of sum-
mer weather in the north temperate zone. There are
the dense tropical forests of the Amazon and of equa-
torial Africa. There frost and drought need not be
feared. This belt of calms and rains, of variable
width and rather indefinite limits, shifts north and
south of the equator after the sun. It is dreaded by
seamen because sailing vessels are apt to have long
delays in Crossing it. The calm belt is generally
CHABACTERISTICS OF ZONES—TROPICS 83
somewhat narrower than the belt of rains, the warm
ascending air being carried north and south, and giv-
ing precipitation beyond the limits of the calm zone.
In striking contrast are the easterly trade winds,
blowing between the tropical high pressure beits and
the equatorial belt of low pressure, and supplying to
the doldrum belt a constant flow of warm air which
already contains a large amount of water vapour,
evaporated from the oceans by the trades, and needs
only a moderate cooling in order to give abundant
rainfall. Of great regularity, embracing about one-
half of the earth’s surface, and adding greatly to the
uniformity of tropical climates, the trades have long
been favourite sailing routes because of the steadi-
ness of their winds, the infrequency of storms, the
brightness of their skies, and the freshness of the air,
all of which are in pleasing contrast with the muggy
and oppressive calms of the doldrums. The most de-
sirable house-sites in the tropics are very commonly
on the top of some elevation, exposed to the trade
wind. The trades are subject to many variations.
Their northern and southem margins shift north and
south af ter the sun; at certain seasons they are
interrupted, often over wide areas near their equator-
ward margins, by the migrating belt of equa-
torial rains and by monsoons; near lands, they
are often interfered with by land and sea breezes;
in certain regions, they are invaded by violent
cyclonic storms. The trades, except where they blow
onto windward coasts, or over mountains, are natu-
84
CLIMATE
rally drying winds, for they blow from higher to lower
latitudes. Some facts seem to show that there is a
descending component in the trades. They cause the
deserts of northern and Southern Africa, eastern Asia,
Australia, and Southern South America. Over the
oceans, the only rains in the trade wind beits are in
the form of passing showers.
The monsoons on the southem and eastern coasts
of Asia are the best known winds of their class. In
the northern summer, the south-west monsoon, warm
and sultry, blows over the latitudes from about 10°
north to and beyond the northem tropic, between
Africa and the Philippines, giving rains over India,
the East Indian Archipelago, and the east coasts of
China. These winds reach a storm velocity over the
Arabian sea. In winter, the south-east monsoon, the
normal, cold-season, Continental outflow from Asia,
combined with the north-east trade, generally cool and
dry, covers the same district, extending as far north
as latitude 30°. Crossing the equator, these winds
reach northern Australia, and the western islands of
the South Pacific, as a north-west rainy monsoon,
while this region in the opposite season has the normal
south-east trade. Other monsoons are found
in the Gulf of Guinea and in equatorial Africa.
Wherever they occur, they control the seasonal
changes.
The most important climatic phenomenon of the
year in the tropics is the rainy season. Tropical
rains are, in the main, summer rains, i. e., they follow,
CHARACTERI8T1C8 OF Z0NE8—TROPICS 85
as a general rule, soon after the “ vertical sun,” 1 the
rainy season coming when the normal trade gives way
to the equatorial belt of rains, or when the summer
monsoon sets in. There are, however, many cases
of a rainy season when the sun is low, especially on
windward coasts in the trades. Tropical rains come
usually in the form of heavy downpours and with
a well-marked diurnal period, the maximum varying
with the locality between noon and midnight. The
conditions at Calcutta, as shown in the accompany-
ing data, are fairly typical.2
DIURNAL DISTRIBUTION OF RAINFALL AT CALCUTTA.
12 P.M. 2 A.M. 50 12 M.—2 P.M. 111
2-4 A.M. 71 2-4 P.M 116
4-6 A.M. 65 4-6 P.M. 120
6-8 A.M. 71 6-8 p.m. 128
£-10 A.M. 58 8-10 p.m. 73
10 A.M. 12 M. 92 10 P.M. 12 P.M. 45
Local influences are, however, very important, and
in many places night rainfall maxima are found.
The tropical rainy season is therefore not to be
thought of as a period of continuous rains, falling
steadily day and night for week after week. The
momings are often fine, with clean air, well washed
by the rains of the preceding afternoon or night.
Woeikof’s detailed studies of tropical rainfalls, as a
whole, lead him to the conclusion that (1) the inten-
sity of tropical rains averages higher than in middle
1 It will be remembered that at all places within the tropics the
sun is vertical twice in the year.
2 Seven year record; expressed in thousandths of the daily mean.
86
CLIMATE
latitudes, but the difference is not great; (2) the
heaviest short downpours have, so far as observation
now goes, occurred in middle latitudes; (8) general,
moderate rainfalls lasting continuously for many
hours, which are common in the temperate zones, are
known in many parts of the tropics and have even
been given special names; (4) the heaviest daily rain-
falls have been noted outside the tropics, as at Cherra-
punji, for example; and (5) it is likely that the most
intense rains in the tropics fall during large tropical
cyclones.
Land and Sea Breezes. The sea breeze is an im-
portant climatic feature on many tropical coasts.
With its regular occurrence, and its cool, clean air,
it serves to make many districts habitable for white
settlers, and has deservedly won the name of “ the
doctor.” On not a few coasts, the sea breeze is a
true prevailing wind. The location of dwellings is
often determined by the exposure of a site to the sea
breeze. For this reason, many native villages are put
as near the sea as possible. The houses of well-to-do
foreigners often occupy the healthiest and most de-
sirable locations, where the sea breeze has a free en-
trance, while the poorer native classes live in the lower,
less exposed and less desirable places. A social
stratification is thus determined by the sea breeze.
Thunderstorms. Local thunderstorms are fre-
quent in the humid portions of the tropics. They
have a marked diurnal periodicity; find their best
opportunity in the equatorial belt of weak pressure
CHARACTERISTICS OF ZONES—TROPICS 87
gradients and high temperature, and- are commonly
associated with the rainy season, being most common
at the beginning and end of the regular rains. In
many places, thunderstorms occur daily throughout
tljeir season, with extraordinary regularity and great
intensity. Lightning is, however, reported as very
seldom doing any damage. Attention has been
called to the fact that the frequent electrical dis-
charges cause the rain water to be relatively rich in
nitric acid. This condition, together with the carbon
dioxide in the rain water and the high temperature
of the same, promotes active and deep rock decom-
position. In higher latitudes, where the ground may
be frozen part of the year, and where the decompos-
ing action of rain water is less, there is less of this
effect. In northem India, hail-storms of great
violence occur, and persons have been killed by
them.
Cloudiness. Taken as a whole, the tropics are not
favoured with such clear skies as is often supposed.
Cloudiness varies about as does the rainfall. The
maximum is in the equatorial belt of calms and rains,
where the sky is always more or less cloudy. The
minimum is in the trade latitudes, where fair skies as
a whole prevail.1 The equatorial cloud belt moves
north and south after the sun. Wholly clear days
are very rare in the tropics generally, especially near
1 Supan, Grundzüge der Physischen ErdJcunde, 3d ed., 1903, Fig.
18, page 53, gives a diagram showing the distribution of rainfall
and cloudiness (also of other elements) according to latitude.
88
CLIMATE
the equator, and during the rainy season heavy clouds
usually cover the sky.
Tropical clouds and rainfall, as a whole, repeat, in
an exaggerated form, the summer conditions of much
of the north temperate zone. Broken skies; cumulus
and cumulo-nimbus clouds; heavy showers or thun-
derstorms—these usually characterise the rainy sea-
son. Skies clear, or flecked with scattered small
cumuli, are typical of the dry season. Wholly over-
cast, dull days, such as are common in the winter of
the temperate zone, occur frequently only on tropical
coasts in the vicinity of cold ocean currents, as in
Peru and on parts of the west coast of Africa. In
these same regions ocean fogs are common.
Intensity of Skylight and Twilight. The inten-
sity of the light from tropical skies by day is trying,
even almost unbearable, to newcomers. The intense
insolation, together with the reflection from the
ground, increases the general dazzling glare under a
tropical sun, necessitating protection of some sort.
The far-famed deep blue of the tropical sky is much
exaggerated. During much of the time, smoke from
forest and prairie fires (in the dry season); dust (in
deserts), and water vapour give the sky a pale, whit-
ish appearance. In the heart of the trade wind beits
at sea, the sky is much more of a deep blue. The
beauties of tropical sunrise and sunset, and of the
tropical night, have, however, not been overrated.
Twilight within the tropics is shorter than in higher
latitudes, but the coming on of night is less sudden
CHABACTERISTICS OF ZONES—TROPICS 89
than is generally assumed. Pechuel-Lösche and
others have shown that it is possible, on the Loango
coast, to read ordinary print twenty to thirty minutes
after sunset.
Climatic Subdivision*. The rational basis for a
classification of the larger climatic provinces of the
torrid zone is found in the general wind systems and
in their control over rainfall. Following this scheme
there are these subdivisions: I. The equatorial belt;
II. The trade wind beits; III. The monsoon beits.
In each of these subdivisions there are modifications,
due to ocean and Continental influences. In general
both seasonal and diurnal phenomena and changes
are more marked in Continental interiors than on the
oceans, islands, and windward coasts. Further, the
effect of altitude is so important that another subdi-
vision should be added to indude IV. Mountain
climates.
I. The Equatorial Belt. Within a few degrees
of the equator, and when not interfered with by other
Controls, the annual curve of temperature has two
maxima following the two zenithal positions of the
sun, and two minima at about the time of the solstices.
This, which is known as the equatorial type of annual
march of temperature, is illustrated in the data
and curves for the interior of Africa, Batavia, and
Jaluit. (Fig. 19).
The greatest range is shown in the curve for the in-
terior of Africa; the curve for Batavia illustrates in-
sular conditions with less range; and the oceanic type,
90
CLIMATE
for Jaluit, Marshall Islands, gives the least range.
At Jaluit, the daily maxima for the entire year are
between 88° and 91.5° and the daily minima between
75° and 77°. This doublé maximum is not a
universal phenomenon, there being many cases where
but a single maximum occurs, as will be seen
later.
TAB LH OF MEAN MONTHLY TEMPERATURES FOR SELECTED
TROPICAL STATIONS1
I. Equatorial Type II. Tropical Type
Conti- nental Insular Marine Continental Monsoon Insular
Africa interior Batavia Jaluit, Marshall Islands Wadi Halfa Alice Springs Nagpur Hono- lulu James- town
Lat. 8.1° N. 8° 11' S. 5° 65' N. 21° 63' N. 23° 38' S. 21°9' N. 21° 18' N. 15° 66' S.
Loog. 23.6° E. 106° 50' E. 169° 40' E. 31° 20' E. 133° 37'E. 79° 11' E. 157° 60'N. 5° 43'W.
Altitude 1837 ft. 23 ft. 10 ft. 426 ft. 1926 ft. 1093 ft. 49 ft. 39 ft.
Jan. 73.4° 77.5° 80.8° 81.3° 85.6° 68.2° 70.0° 74.7°
Feb. 77.2° 77.7° 81.0° 68.6° 83.3° 73 8° 70.3° 75.9°
Mar. 83.8° 78.4° 80.6° 73.0° 77.9° 83 7° 70.9° 73.8°
April May 85.3° 79.3° 80.4° 81.0° 68.5° 90.3° 72.9° 75.0°
83.7° 79.5° 80.4° 87.1® 80.6° 94.3° 74.3® 88.9°
Tune 81.5° 78.8° 80.2° 91.4° 54.0° 85.6° 76.1° 70.5°
July 78.4° 78.3° 80.2° 93.4° 51.8° 80.1° 77.2° 71.8°
Aug. 75.7° 78.6° 80.4° 91.6° 59.4° 80.2° 77.5° 69.4°
Sept. 77.7° 79.3° 80.4° 87.1° 66.6° 80.4° 77.2° 87.6°
Oct. 78.1° 79.5° 80.8° 83.1° 73.4° 78.6° 76.5° 86.7°
Nov. 75.7° 79.0° 80.8° 71.4° 79.7® 72.3° 73.8° 67.8°
Dec. 72.0° 78.1° 80.6° 84.8° 82.8° 66.7° 71.4° 71.8°
Mean 78.6° 78.8° 80.6° 79.3° 70.3° 79.5° - 73.9° 71.1°
Range 12.4° 2° 0.8° 32.1° 33.8° 27.6° 7.5 10.2°
As the belt of rains swings back and forth across
the equator after the sun, there should be two rainy
seasons with the sun vertical, and two dry seasons
when the sun is farthest from the zenith, and while
1 Given to nearest tenth of a degree Fahr.
CBARACTERISTIC8 OF ZONES—TROPICS 91
the trades blow. These conditions prevail on the
equator, and as far north and south of the equator
(about 10°-12°) as sufficiënt time elapses between
the two zenithal positions of the sun for the two rainy
Fig. 19. Annual March of Temperature: Equatorial Type.
A: Africa, interior. B: Batavia. J: Jaluit, Marshall Islands.
seasons to be distinguished from one another. In
this belt, under normal conditions, there is, therefore,
no dry season of any considerable duration. The
doublé rainy season is clearly seen in equatorial
Fig. 20. Annual March of Rainfall
in the Tropics
S. A: South Africa. Q: Quito. S. P:
Sao Paulo. M: Mexico. H: Hilo.
P. D: Port Darwin.
92
CHABACTERISTICS OF ZONES—TROPICS 93
Africa and in parts of equatorial South America.
The maxima lag somewhat behind the vertical sun,
coming in April and November, and are unsymmetri-
cally developed, the first maximum being the principal
one. The minima are also unsymmetrically devel-
oped, and the so-called “ dry seasons ” are seldom
wholly rainless. In this equatorial belt, the annual
range of rainfall is generally below 20%; in the west-
ern portion of the Malay Archipelagd and on the
upper Amazon, it is below 10%. In these latitudes,
therefore, the distribution of rainfall is not unlike that
in extra-tropical latitudes which are under the marine
regime of rainfall, there being precipitation at all
seasons.
This rainfall type with doublé maxima and minima
has been called the equatorial type, and is illustrated
in the following data and in the curves for south
Africa and Quito. (Fig. 20).
The mean annual rainfall at Quito is 42.12 inches.
These doublé rainy and dry seasons are easily modi-
fied by other conditions, as by the monsoons of the
Indo-Australiaii area, for example, so there is no
rigid belt of equatorial rains extending around the
world. In South America, east of the Andes, the
distinction between rainy and dry seasons is often
much confused. In this equatorial belt, the cloudi-
ness is high throughout the year, averaging .7 to .8,
with a relativeljj small annual period. The data and
curve following are fairly typical, but the annual
period varies greatly under local Controls. (Fig. 21).
94
-
CLIMATE
TABLB SHOWING MONTHLY DISTRIBUTION OP RAINPALL POR
SELECTED TROPICAL STATIONS1
Tropics
Doublé Rainy Single Rainy Season
Season Equatorial Margin of Tropics Trade Rains Monsoon . Rains
Southem Northem
Southern Africa Quito S&o Paulo Mexico Hilo Port Darwin
Latitude 6° S. Equator 23.5° S. 19.4° N. 19.7° N. 12.5° S.
Jan. 86 77 195 7 79 241
Feb. 80 92 156 9 94 215
March 123 115 103 26 86 166
April May 195 165 58 26 94 61
91 109 60 85 66 23
June 10 35 46 174 55 1
July 7 25 19 180 82 0
Aug. 17 52 31 207 81 2
Sept. 37 60 60 179 73 5
Oct. 61 91 82 79 88 38
Nov. 188 94 74 20 95 72
Dec. 105 85 116 8 107 176
TABLB SHOWING MONTHLY DI8TRIBUTION OP CLOUDINESS IN AN
BQUATORIAL CLIMATE. (CAMEROONS; GABOON. LAT. 3°
N., WEST AFRICA.)
Jan. Feb. Mar. Apr. May June July Aug. Sept. Oct. Nov Dec. Year
5.4 6.3 7.0 7.2 7.4 7.7 8.9 8.6 8.4 8.0 7.4 6.6 7.4
At greater distances from the equator than about
10° or 12°, the sun is still vertical twice a yearwithin
the tropics, but the interval between these two dates
is so short that the two rainy seasons merge into one,
in summer, and there is also but one dry season, in
1 The figures in this table are thousandths of the mean annual
rainfall. In the first column of the table, the average of a con-
siderable number of stations is given.
CHARACTERISTICS OF ZONES—TROPICS 95
winter. This is the so-called tropical type of rain-
fall,1 and is found where the trade beits are encroached
upon by the equatorial rains during the migration of
these rains into each hemisphere. It is illustrated in
E: Equatorial type. M: Monsoon type
the data and curves for Sao Paulo, Brazil, and for the
city of Mexico (see rainfall table above and Fig. 20).
The mean annual rainfall at Sao Paulo is 54.18
inches, and at Mexico 22.99 inches.
The districts of tropical rains of this type lie along
the equatorial margins of the torrid zone, outside of
the latitudes of the equatorial type of rainfall. The
rainy season becomes shorter with increasing distance
from the equator. The weather of the opposite sea-
sons is strongly contrasted. The single dry season
lasts longer than either dry season in the equatorial
1 Supan calla it the margimU type of the tropics.
96
CLIMATE
belt, reaching eight months in typical cases, with the
wet season lasting four months. The lowlands often
become dry and parched during the long, dry trade
wind season (winter), and vegetation withers away,
while grass and flowers grow in great abundance
and all life takes on new activity during the time
when the equatorial rainy belt, with its calms, variable
winds, and heavy rains, is over them (summer). The
Sudan lies between the Sahara and the equatorial
forests of Africa. It receives rains, and its vegeta-
tion grows actively, when the doldrum belt is north
of the equator (May-August). But when the trades
blow (December-Match), the ground is parched and
dusty. The Venezuelan llanos have a dry season in
the northem winter, when the trade blows. The
rains come in May-October. The campos of Brazil,
south of the equator, have their rains in October-
April, and are dry the remainder of the year. The
Nile overflow results from the rainfall on the mount-
ains of Abyssinia during the northward migration
of the belt of equatorial rains.
Simple tropical rainfalls, as shown in the above
curves, are typical of large areas, but they are not in-
frequently complicated by association with trade or
monsoon rains, as in the West Indies, Central Amer-
ica, and India. The true doldrum rains may come
along the polar margin of the equatorial low-pressure
belt, when this belt is moving equatorward, followed
by the trades.
The so-called tropical type of temperature variation,
Fig. 22. Annual March of Tempera- .
ture: Tropical Type
W: Wadi Halfa. N: Nagpur. A: Alice
Springs. H: Honolulu. J: Jamestown,
St. Helena
7
97
98
CLIMATE
with one maximum and one minimum, is illustrated
in the data given in the table on page 90, and
in the accompanying curves for Wadi Halfa, in Up-
per Egypt; Alice Springs, Australia; Nagpur, India;
Honolulu, Hawaii, and Jamestown, St. Helena.
The effect of the rainy season is often shown in a
displacement of the time of maximum temperature to
an earlier month than the usual one. During the
rains, the temperature is apt to remain constant, as
in the case of Nagpur, and of other stations in
India, Mexico, and the interior of Senegambia. This
type of temperature curve is characteristic of most
of the tropics outside of the latitudes reached by the
equatorial belt.
II. Trade Wind Beits. The trade beits near
sea-level are characterised by fair weather, steady
winds, infrequent light rains or. even an almost com-
plete absence of rain; very regular, although slight, *
annual and diurnal ranges of temperature, and a
constancy and regularity of weather which is more
truly “ temperate ” than that of most of the so-called
temperate zone. The climate of the ocean areas in
the trade wind beits is indeed the simplest and most
equable in the world, the greatest extremes—and even
these are moderate—being found to leeward of the
larger lands, where the Continental conditions are
carried offshore by the prevailing winds. On the
lowlands swept over by the trades, beyond the polar
limits of the equatorial rain belt (roughly between
lats. 20° and 80°), are most of the great deserts of the
CHARACTERI8TICS OF ZONES—TROPICS 9Ö
world. These deserts extend directly to the water’s
edge on the leeward, western coasts of Australia,
south Africa, and South America. In the two lat-
ter regions, the desert conditions are further helped
by the presence of cold ocean currents offshore. Be-
cause of their great extent, these trade wind deserts
constitute one of the most important climatic districts
in the world.
The ranges and extremes of temperature are much
greater over the deserts, especially the Continental in-
teriors, than over the oceans of the trade wind beits.
Minima of 32° or less occur during clear, quiet nights,
and daily ranges of over 50° are common. The mid-
summer mean temperature rises above 90°, with noon
maxima of 110°, or more, in the non-cloudy, dry air
of a desert day. The days, with high, dry winds,
carrying dust and sand, with extreme heat, accent-
uated by the absence of vegetation, are disagreeable
or even dangerous to life; but the calmer nights, with
active radiation under clear skies, are much more
comfortable. The nocturnal temperatures are even
not seldom too low for comfort in the cooler season,
when thin sheets of ice may form. Under the strong
insolation by day and the quick cooling by night,
rocks in the deserts split and break up. On the whole,
however, man is less susceptible to the larger tem-
perature ranges in tropical deserts than to the smaller
ones in the equatorial belt, because of the lower rela-
tive humidity in the former case. In the trade wind
deserts, as in other arid regions, man is nomadic.
100
CLIMATE
While the trades are drying winds as long as they
blow strong over the oceans, or over lowlands, they
contain a large amount of water vapour, and readily
beoome rainy if they are cooled during an ascent
over a mountain or highland. Hence the windward
(eastern) sides of mountains or bold coasts in the
trade wind beits are well watered, while the leeward
sides, or interiors, are dry. Mountainous islands in
the trades, like the Hawaiian Islands, many of the
East and West Indies, the Philippines, Bomeo, Cey-
lon, Madagascar, Teneriffe, etc., show marked diver-
gences of this sort. The eastern coasts of Guiana,
Central America, south-eastern Brazil, south-eastem
Africa, and eastern Australia are well watered, while
the interiors are very dry in the two last-named coun-
tries. The eastern highland of Australia constitutes
a more effective barrier than that in south Africa;
hence the Australian interior has a more extended
desert. South America in the south-east trade belt is
not well enclosed on the east, and the most and por-
tion is an interior district near the eastern base of
the Andes, where the land is low. Even far inland,
the Andes again provoke precipitation along their
eastern base, and the narrow Pacific Coastal strip, to
leeward of the Andes, is a very pronounced desert
from the equator to about lat. 30° S. The cold ocean
waters, with prevailing southerly (drying) winds
alongshore, are additional factors in causing this
aridity. The Peruvian climatic province is abnorm-
ally cool. Highlands in the trade beits are therefore
CE ARA CTERISTICS OF ZONES—TROPICS 101
moist on their windward slopes—even in deserts,
mountains provoke local rainfall, tree growth, and
local streams—and becomes oases of luxuriant plant
growth, while close at hand, on the leeward sides, dry
savannas or deserts may be found. The damp, rainy
and forested windward (N.E. trade) side of Central
America was, from the earliest days of European oc-
cupation, left to the natives, while the centre of civili-
sation was naturally established on the more open and
sunny south-western side.
The rainfall associated with the conditions just de-
scribed is known as the trade type. These rains have
a' maximum in winter, when the trades are most ac-
tive, this being a departure from the general rule of
summer rains in the tropics. In cases where the trade
blows steadily throughout the year against mount-
ains or bold coasts, as on the Atlantic coast of Cen-
tral America, there is no really dry season. The data
and curve for Hilo (mean annual rainfall 145.24
inches), on the windward side of the Hawaiian
Islands, show typical conditions (see Fig. 20). The
tropical rains are convectional, and therefore prefer
the warm season; the trade rains are orographic, and
have a winter maximum.
The trade type of rainfall is often much compli-
cated by the combination with it of the tropical type
and of the monsoon type (see next paragraph).
Zanzibar, for example, has its principal maximum of
rainfall in April, which is pure tropical, and has a
secondary maximum in December, which is trade.
102
CLIMATE
Again, on the lee of highlands which receive a winter
maximum on their windward slopes, summer rains
may occur at the time when the trade is weakest, and
the otherwise long dry season is interrupted by scat-
tering showers. In the Malay archipelago, there are
complications of equatorial and trade rains; likewise
in the West Indies. Trade rains often have a tend-
ency to give precipitation both day and night, while
torrid zone rains generally prefer the day.
III. Monsoon Beits. In a typical monsoon re-
gion, such as that of India, eastern Asia, and the ad-
jacent islands, the rains follow the vertical sun, and
therefore have a simple annual period much like that
of the tropical type above described, the dry season
coming when the sun is lowest (winter). This mon-
soon type of rainfall is well illustrated in the data
and curve for Port Darwin (mean annual rainfall
62.72 inches), in Australia. This summer monsoon
rainfall results from the inflow of a large body of
warm, moist air from the sea on to a land area; a con-
sequent retardation of the velocity of the air currents,
as the result of friction, and an ascent of the air, the
rainfall being particularly heavy where the winds.
have to climb over high lands. Thus, in India, the
precipitation is heaviest at the head of the Bay of
Bengal, where Cherrapunji, at the height of 4455
feet in the Khasi Hills, has a mean annual rainfall of
between 400 and 500 inches; along the southem base
of the Himalayas (60 to 160 inches); on the bold
western coast of the peninsula (80 to 120 inches and
CHARACTERISTICS OF ZONES—TROPICS 103
over), and on the mountains of Burma (up to 160
inches). In the rain-shadow of the Western Ghats,
the Deccan often suffers from drought and famine
unless the monsoon rains are abundant and well dis-
tributed, and the decreasing rainfall up the Ganges
valley leaves the Indus plain with a deficiency (less
than five inches). The prevailing direction of the
rainy monsoon wind in India is south-west; on the
Pacific coast of Asia, south-east. This monsoon dis-
trict is very large, including the Indian Ocean, Ara-
bian Sea, Bay of Bengal, and adjoining Continental
areas; the Pacific coast of China, the Yellow and
Japan seas, and numerous islands from Bomeo to
Sakhalin on the north and to the Ladrone Islands on
the east. Where the seasons are clearly defined in
India, they are three in number: a cool, dry season
(winter) when northerly trade winds prevail, and
when there is little or no rainfall except in the north-
em provinces, where moderate cyclonic storms oc-
casionally occur; a wet season, sultry and oppressive,
with the inflowing south-west monsoon of summer;
and a hot, dry season before the beginning of the
rains. The beginning of the monsoon rains usually
comes suddenly (“ burst ”), with heavy thunder-
storms. A typical temperature curve for a monsoon
district is that for Nagpur, in the Indian Deccan
(see Fig. 22), and a typical cloudiness curve is given
in Fig. 21, the maximum coming near the time of the
vertical sun, in the rainy season, and the minimum in
the dry season.
104
CLIMATE
TABLE SHOWING MONTHLY DISTRIBUTION OP CLOUDINESS IN A
MONSOON CLIMATE (BENGAL, LAT. 23.5° N.).1
Jan. Feb. Mar. Apr. May June July Aug. Sept. Oct. Nov. Dec. Year
1.9 1.8 2.6 3.0 4.5 7.5 8.5 8.4 7.5 4.3 2.5 1.8 4.5
In the Australian monsoon region, which reaches
across New Guinea and the Sunda Islands, and west
of Australia, in the Indian Ocean, over latitudes
0°-10° S., the monsoon rains come with north-west
winds in the period between November and March or
April. The northern portion of Australia is thus
watered by zenithal summer rains, and the Southern
portions of Sumatra, Borneo, and Java are also un-
der the influence of this north-west monsoon. The
essential features of the whole Indo-Australian mon-
soon belt, therefore, are a fairly uniform distribution
and small annual range of temperature; and well-
marked periodic rains, coming with north-west or
south-west winds according to the hemisphere.
The general rule that eastern coasts in the tropics
are the rainiest finds exceptions in the case of the rainy
western coasts in India and other districts with simi-
lar rains. On the coast of the Gulf of Guinea, for
example, there is a small rainy monsoon area during
the summer; heavy rains fall on the seaward slopes of
the Cameroon Mts. Not far inland, Baliburg shows
a doublé maximum of the equatorial type. Gorée,
lat. 15° N., on the coast of Senegambia, gives a fine
example of a rainy (summer) and a dry (winter)
monsoon. A case of a special kind is the Somali
1 Five stations.
CHABACTERISTICS OF ZONES—TROPICS 105
coast, which trends N.E-S.W., and is therefore
parallel with both monsoons. Hence at no season
can it become very rainy, and mean annual rainfalls
of 40 inches , are not recorded until the coast takes a
turn to the south, at Mombasa.
Numerous combinations of equatorial, trade and
monsoon rainfalls are found, often creating great
complexity. In the case of Port Darwin, the station
is near enough to the equator to have two rainy sea-
sons (equatorial type) when the sun is vertical, as is
frequently the case in the West Indies and Central
America in the same latitude. The rainiest month,
however, is January, between the two times of verti-
cal sun, but during the height of the monsoon, there
being a rainy season of four months and a dry season
of eight months. The monsoon thus interferes with
the typical occurrence of equatorial rains. It is also
true that the dry season in monsoon districts is drier
than the two dry seasons of the equatorial type.
Batavia, on the island of Java, has simple monsoon
rains. Buitenzorg, on the same island, has a mon-
soon maximum in January, two months bef ore the
sun is vertical for the first time, and it has a regular
tropical maximum of rainfall in October, following
the second zenithal position of the sun. The north
coast of Ceram, in the Moluccas, has north-west sum-
mer monsoon rains, with a maximum in February,
while the south coast has winter rains, with the south-
east trade. The rainy and dry seasons thus come
under different conditions and at opposite times on
106
CLIMATE
the two coasts. These two sets of conditions are
often very close together, with a divide between them.
On the island of Hawaii, Hilo, on the east side, is
exposed to the,north-east trade and has a winter maxi-
mum of rainfall. Kailua, on the lee side, has about
one-third as much rainfall, with a summer maximum.
The islands of the East Indian archipelago furnish
many examples of such curious complications. The
eastern coast of Madagascar has south-east trade
winds fairly uniformly through the year, while the
interior and west coast have a summer maximum—
the normal tropical rainfall season.
IV. Mountain Climate. Within the tropics, alti-
tude is chiefly important because of its effect in tem-
pering the heat of the lowlands, especially at night.
If tropical mountains are high enough, they carry
snow the year around, even on the equator, and the
zones of vegetation may range from the densest
tropical forest at their base to the snow on their sum-
mits. The highlands and mountains within the
tropics are thus often sharply contrasted with the
lowlands, and offer more agreeable and more healthful
conditions for white settlement. They are therefore
often sought out by residents from colder latitudes
as the most attractive resorts. In India, the hill sta-
tions are crowded during the hot months by civilian
and military officials, and it has been well said that
India is ruled from 7,000 feet above sea-level. The
climate of many tropical plateaus and mountains
has the reputation of being a “ perpetual spring.”
CHARACTERISTICS OF Z0XE8—TROPICS 107
Thus, on the interior plateau of the tropical Cordil-
leras of South America, and on the central plateau of
tropical Africa, the heat is tempered hy the altitude,
while the lowlands and coasts are very hot. The
rainfall on tropical mountains and highlands often
differs considerably in amount from that on the
lowlands, and other features common to mountain
climates the world over are also noted. But the
main emphasis is rightly laid upon the temperature.
-
CHAPTER V
THE CHARACTERISTICS OF THE ZONES: II.—THE
TEMPERATE ZONES
General: “ Temperate ” Zones—Temperature—Pressure and Winds
—Rainfall—Humidity and Cloudiness—Seasons: Their Effects
on Man—Weather—Climatic Subdivisions—South Temperate
Zone—Sub-tropical Beits: Mediterranean Climates—North
Temperate Zone: Western Coasts—Interiors—Eastern Coasts
—Mountain Climates.
General: “Temperate" Zone». The so-called
“ temperate ” zones occupy about one-half of the
earth’s surface. As a whole, they are temperate only
in that their mean temperatures and their physiolo-
gical effects are intermediate between those of the
tropics and those of the polar zones. The modifica-
tions of solar climate which result from the distribu-
tion and influence of land and water are greatest in
the temperate zones. The north temperate zone in-
cludes the greatest known extremes of temperature.
If the use of the word “ temperate ” were not so
firmly established it would be well to change the name
to intermediate, or to middle.1
1 North-middle and south-middle would then distinguish the
zones in the two hemispheres. (See W. M. Davis: The Temperate
Zones, Joum. Geogr., vol. i, 1897, pp. 139-143.) “ Temperate ” does,
however, apply fairly well to the south temperate zone.
108
CHARACTERISTICS OF ZONES—TEMPERATE 109
A marked changeableness of the weather is a strik-
ing characteristic of these zones. Apparently irreg-
ular and haphazard, these continual weather changes
nevertheless run through a fairly systematic series,
although they are essentially non-periodic. Climate
and weather are by no means synonymous over most
of the extra-tropical latitudes.
Temperature. The mean annual temperatures at
the margins of the north temperate zone differ by
more than 70°. The ranges between the mean tem-
peratures of hottest and coldest months reach 120° at
their maximum in north-eastem Siberia, and 80° in
North America. A January mean of —60° and a
July mean of 95°, and maxima of over 120° and
minima of —90°, occur in the same zone. In the dis-
tricts of lowest winter minima, the mean summer tem-
peratures exceed 85°, and in portions of the districts
of highest mean summer maxima, the mean winter
minima fall below 82°. Such great ranges character-
ise the extreme land climates. Under the mild in-
fluence of the oceans, the windward west coasts have
much smaller ranges than the interiors; the seasonal
differences increase inland. The annual ranges in
the middle and higher latitudes exceed the diurnal,
the conditions in much of the torrid zone being ex-
actly reversed. Over much of the oceans of the tem-
perate zones the annual range is less than 10°. In
the south temperate zone there are no extreme ranges,
the maxima, slightly over 80°, being near the margin
of the zone in the interior of South America, south
110
CLIMATE
Africa, and Australia. In these same localities, the
diurnal ranges, however, rival those of the north
temperate zone.
The north-eastern Atlantic ocean and north-west-
em Europe are about 85° too warm for their latitude
in January, while north-eastem Siberia is 80° too cold.
The lands north of Hudson’s Bay are 25° too cold,
and the waters of the Alaskan Bay 20° too warm.
In July, and in the southem hemisphere, the anoma-
lies are small. The lands which are the centre of
civilisation in Europe average too warm for their lati-
tudes. These lands are the most truly “ temperate ”
portion of the north temperate zone. The north-
west coast of North America is much the same. The
diurnal variability of temperature is greater in the
north temperate zone than elsewhere in the world,
and the same month may differ greatly in its charac-
ter in different years. One winter in higher latitudes
may have much snow, and temperatures below
normal; the next may give much rain instead of snow,
and the ground remain unfrozen. One summer may
be very favourable for crops; the next may give a
poor harvest.
From the point of view of temperature, these zones
may be considered in three divisions: (1) the sub-
tropical, (2) the “temperate” latitudes, and (8) the
sub-polar. The annual temperature curve has one
maximum and one minimum. In the Continental
type, the times of maximum and minimum are about
one month behind the maximum and minimum in-
CHABACTERISTICS OF ZONES—TEMPERATE 111
gnlaftnn dates. In the marine type, the retardation
may amount to nearly two. months. Coasts and
islands have a tendency to a cool spring and warm
autumn; continents, to similar temperatures in both
spring and fall.
Presmre and Winds. The prevailing winds are
the “ westerlies,” which occupy about as much of the
earth’s surface as do the easterly trades. The wester-
lies are, however, much less regular than the trades.
They vary greatly in velocity in different regions and
in different seasons, from a light wind to a gale of
fifty or more miles an hour. They are stronger in
winter than in summer. They are much interfered
with, especially in the higher northem latitudes, by
seasonal changes of temperature and pressure over the
continents, whereby the latter establish, more or less
successfully, a system of obliquely outflowing winds
in winter and of obliquely inflowing winds in sum-
mer. On the eastern coast of Asia there is a com-
plete reversal in wind direction at the opposite
seasons, but usually the seasonal shift is much less
than 180°. In summer, when the lands have low
pressure, the northem oceans are dominated by great
oval areas of high pressure, with outflowing spiral
eddies, while in winter, when the northem lands have
high pressure, the northem portions of the oceans
develop cyclonic systems of inflowing winds over
their warm waters. All these great Continental and
oceanic systems of spiraling winds are important
climatic Controls.
CLIMATE
112
The westerlies are also much confused and inter-
rupted by storms. Hence their designation of stormy
•westerlies. A constant succession of cyclones, and
the accompanying anticyclones, travelling along with
the prevailing westerlies, causes the latter very fre-
quently to change direction in order to become part
of a cyclonic or an anticyclonic whirl. In these
storms, velocities of eighty or more miles an hour
may be reached at sea. So common are such in-
terruptions that the prevailing westerly wind direc-
tion is often difficult to discem without careful
observation. Cyclonic storms are most numerous
and best developed in winter. The irregular press-
ure changes usually wholly mask the faint diurnal
variation of the barometer which is so characteristic
of the tropics, and which becomes less and less marked
with increasing latitude. Although greatly inter-
fered with near sea-level by Continental changes of
pressure, by cyclonic and anticyclonic whirls, and by
local inequalities of the surface, the eastward move-
ment of the atmosphere remains very constant aloft.
The drift of the higher clouds, and wind observations
on mountains, show clearly that the upper currents
blow with great steadiness from westerly points, the
departures being temporary, and under the control
of passing cyclones or anticyclones. The south tem-
perate zone is chiefly water. Hence the westerlies
are but little distorted by Continental effects. They
are strong and steady, and almost as regular as the
trades. “ Roaring forties ” is a well-known designa-
CHARACTERISTICS OF ZONES—TEMPERATE 113
tion for the Southern middle latitudes, and between
latitudes 40° and 60° S. the “ brave west winds ” blow
with a constancy and a velocity found in the northern
hemisphere only on the oceans, and then in a modi-
fied form. Storms, frequent and severe, cfyaracter-
ise these southem hemisphere westerlies, and easterly
wind directions are temporarily noted during their
passage. Voyages to the west around Cape Horn
against head gales, and in cold, wet weather, are
much dreaded. South of Africa and Australia, also,
the westerlies are remarkably steady and strong.
The winter in these latitudes is stormier than the
summer, but the seasonal difference is less than that
north of the equator.
Between trades and westerlies lies a debatable belt
of high pressure, shifting seasonally. Within it,
stormy westerlies and drying trades alternately hold
sway. It is the sub-tropical belt, a favoured climatic
region, where invalids seek health, and an escape from
the rigors of a cold winter is found by many who
have time and means to leave their northem homes.
Rainfall. Rainfall is fairly abundant over the
oceans, where evaporation is large, and also over a
considerable part of the lands (30-80 inches, and
more). It comes chiefly in connection with the usual
cyclonic storms, or in thunderstorms, but altitude
often serves locally to increase this precipitation. So
great are the differences, geographic and periodic, in
rainfall, produced by differences in temperature,
topography, cyclonic conditions, etc., that none but
8
114
CLIMATE
the most general rules can be laid down. The
equatorward margin of the temperate zone rains is
clearly defined on the west coasts, at the points where
the coast deserts are replaced by beits of light or
moderate rainfall. Bold west coasts, on the polar
side of lat. 40°, are very rainy, having 100 inches and
more a year in the most favourable situations. The
hearts of the continents, far from the sea, and especi-
ally when well enclosed by mountains, or when blown
over by cool ocean winds which warm in Crossing the
land, have light rainfall (less than 10-20 inches).
East coasts, receiving rain from moist winds blowing
in from the adjacent oceans as monsoons, or in front
of cyclonic stormt, are wetter than interiors, but drier
than west coasts. Winter is the season of maximum
rainfall over oceans, islands, and west coasts, for the
westerlies are then most active, cyclonic storms are
then most numerous and best developed, and the cold
lands chili the inflowing damp air. At this season,
however, the low temperatures, high pressures, and
tendency to outflowing winds over the continents are
unfavourable to rainfall, and the interior land areas,
as a rule, then have their minimum. The warmer
months bring the maximum rainfall over the conti-
nents. Then conditions are favourable for inflowing
damp winds from the adjacent oceans; there is the
best opportunity for convection; thunder-showers
readily develop on the hot aftemoons; the capacity of
the air for water vapour is greatest. Continents,
from equator to higher latitudes, thus have a tend-
CHARACTERISTICS OF ZONES—TEMPERATE 115
ency to maximum rainfall in the warm season; sum-
mer rains, as a whole, predominate over the lands.
The marine type of rainfall, with a winter maximum,
extends in over the western borders of the continents,
and is also found in the winter rainfall of the sub-
tropical beits. These winter rains are in some respects
like the winter rains on windward coasts in the trades.
Coastal lands reached by them are well watered, and
droughts need not be feared. Rainfalls are heaviest
along the tracks of most frequent cyclonic storms.
For Continental stations, the typical daily march of
rainfall is shown in the accompanying data for Berlin
and New York.
DAILY MARCH OF RAINFALL (THOIJSANDTHS OF THB DAILY
MEAN).
I. Continental Type.
Hours. Berlin. New York.
12 p.m.—2 a.m...........................76
2-4 83
4-6 74
6-8 69
8-10 ..........................62
10-Noon ........................68
Noon—2 p.m.............................85
2-4 105
4-6 104
6-8 113
8-10 83
10-12 p.m.......................78
79
85
79
80
74
81
83
95
91
90
85
78
The chief maximum is in the afternoon, and the
secondary maximum comes in the night or early
moming. The chief minimum comes between 10 a.m.
and 2 p.m. Coast stations generally have a night
116
CLIMATE
maximum, and a minimum between 10 a.m. and 4
p.m., as illustrated in the following data for Valentia.
DAILY MARCH OF RAINFALL AT YALENTIA (THOUSANDTHS OF
DAILY MEAN)
II. Marine Type.
12 p.m—2 a.m..............................88
2-4 93
4-6 93
6-8 90
8-10 84
10-Noon ............................76
Noon—2 p.m................................74
2-4 75
4-6 80
6-8 ...............................82
8-10 ..............................82
10-12 p.m...........................83
Humidity and Cloudiness. Arrhenius gives the
mean cloudiness for different latitudes as follows:
70® N. 60° 50° 40° 30° 20° 10° Eq. 10° 20° 30° 40° 50° 60° S.
59 61 48 49 42 40 50 58 57 48 46 50 66 75
The higher latitudes of the temperate zones thus
have a mean cloudiness which equals and even exceects
that of the equatorial belt. The amounts over the
oceans and coasts are greater than inland. The beits
of minimum cloudiness are at about lat. 30° N. and
S. Over the Continental interiors, the cloudiest sea-
son is summer, but the amount is never very large.
Otherwise, winter is generally the cloudiest season,
with a fairly high mean annual amount.
The absolute humidity, as a whole, decreases as the
CHARACTERISTICS OF ZONES—TEMPERATE 117
temperature falls. The relative humidity averages
ninety per cent., more or less, over the oceans, and is
high under the clouds and rain of cyclonic storms, but
depends, on land, upon the wind direction; winds
from an ocean or from a lower latitude being damper,
and those from a continent or from a colder latitude
being drier.
Seaaons: Their Effects on Man. Seasons in the
temperate zones are classified according to tempera-
ture—not, as in the tropics, by rainfall. The four
seasons are important characteristics of these zones,
especially of the middle latitudes of the north tem-
perate zone. Here spring and autumn intervene as
transition seasons between the colder winter with
snow, and warmer summer with more or less rain.
Towards the equatorial margins of the zones, the dif-
ference in temperature between summer and winter
becomes smaller, and the transition seasons weaken
and even disappear. At the polar margins, the
change from winter to summer, and vice versa, is so
sudden that there also the transition seasons dis-
appear. These seasonal changes are of the greatest
importance in the life of man.
Weather. An extreme changeableness of the
weather, depending on the succession of cyclones and
anticyclones, is another characteristic. For most of
the year and most of the zone, settled weather is un-
known. The changes are most rapid in the northern
portion of the north temperate zone, especially on
the continents, where the cyclones travel fastest. The
118
CLIMATE
nature of these changes depends on the degree of de-
velopment, the velocity of progression, the track, and
other conditions of the disturbance which produces
them. The changes may be sudden and marked, or
faint and slow; the wind may back or veer; the pre-
cipitation may be heavy or light; the wind velocity
may be light, or of hurricane force; anticyclones may
be clear, or may have clouds, and not infrequently,
precipitation. There is an almost endless variety of
such examples. The detailed study of these varying
phases of cyclonic and anticyclonic weather Controls
belongs to meteorology. It suffices here to say that
the particular weather types resulting from this con-
trol give the climates their distinctive character, and
that the study of climate through these types is the
only method of appreciating the actual conditions.
Annual and monthly averages of the different cli-
matic elements alone are misleading, and give but a
lifeless picture. The cyclonic unit, although its period
is irregular and of varying length, is an essential
basis of computation and comparison.
The weather types vary with the season and with
the geographical position. They result from a com-
bination, more or less irregular, of periodic, diurnal
elements, under the regular control of the sun, and
of non-periodic cyclonic and anticyclonic élements.
In summer, on land, when the cyclonic element is
weakest and the solar control is the strongest, the
dominant types are associated with the regular
changes from day to night. Daytime cumulus
CHARACTERISTICS OF ZONES—TEMPERATE 119
clouds; diurnal variation in wind velocity; afternoon
thunderstorms, with considerable regularity, char-
acterise the warmest months over the continents and
present an analogy with tropical conditions. Cy-
clonic and anticyclonic spells of hotter or cooler,
rainy or dry, weather, with varying winds differing
in the temperatures and the moisture which they
bring, serve to break the regularity of the diurnal
types. On the oceans, the diurnal characteristics are
much less marked.
In winter, the non-periodic, cyclonic control is
strongest. Local conditions of heat and cold become
subordinate to the general control by the cydone,
which imports weather from a distance. The irregu-
lar changes from clear to cloudy, from warmer to
colder, from dry air to snow or rain, extend over
large areas and show little diurnal control. Spring
and autumn are transition seasons and have transition
weather types. In spring, the growing diurnal
quality is marked by the increasing importance of
local Controls; the appearance of convectional pheno-
mena such as spring rains; the struggle between the
cyclonic and the solar Controls of temperature, now
one and now the other being paramount, but the lat-
ter gaining and the former losing. Cold spells, with
cyclonic winds and clouds, recall winter. Warm
spells, with marked diurnal temperature range, pre-
sage summer. In autumn, the decreasing frequency
and importance of diurnal phenomena, such as thun-
der-showers, high afternoon temperatures, and the
120
-
CLIMATE
like; the active radiation and cooling during the
longer nights, with resulting fogs; and the increas-
ing control by the cyclone, point to winter’s coming.
Weather types thus differ with the seasons. They
differ also in Continental and marine climates. They
differ according to topography and cyclonic and anti-
cyclonic tracks. The oceans in the south temperate
zone have a constancy of non-periodic cyclonic
weather changes through the year which resembles
only faintly that over the oceans of the northem hemi-
sphere. Winter types differ little from summer
types. The diurnal control is never very strong.
Stormy weather prevails throughout the year, al-
though the weather changes are more frequent and
stronger in the colder months.
Climatic Subdivisions. From whatever point of
view the temperate zones be considered, it is clear that
there are fundamental differences between the north
and south temperate. The latter is sufficiently in-
dividual to be given a place by itself. The marginal
sub-tropical beits must also be considered as a separ-
ate group by themselves. The north temperate zone
as a whole includes large areas of land, stretching over
many degrees of latitude, as well as of water. Hence
it embraces so remarkable a diversity of climates that
no single district can be taken as typical of the whole.
lts climate has been called “ a crazy quilt of patches.”
It is a zone of marked seasonal variations and of
great extremes, annual, diurnal, cyclonic. The
simplest and most rational scheme for a classification
CHARACTERISTICS OF ZONES—TEMPERATE 121
of these climates is based on the fundamental differ-
ences which depend upon land and water, upon the
prevailing winds, and upon altitude. Thus there are
the ocean areas and the land areas. The latter are
then subdivided into western (windward) and eastern
(leeward) coasts, and interiors. Mountain climates
remain as a separate group.
South Temperate Zone. If the climate of the
north temperate zone is “ a crazy quilt of patches,”
that of the south temperate is a piece of fairly uni-
form texture and appearance throughout. This is
the effect of the large ocean surface. The whole
meteorological régime is more uniform than in the
northem zone. Although the solar climate of the
southem hemisphere is more severe than that of the
northem, the physical climate is very much less ex-
treme. It has been pointed out that this zone may
properly be called “temperate”; that its tempera-
ture changes are small; its prevailing winds are
stronger and steadier than in the northern hemisphere;
its seasons more uniform; its weather prevailingly
stormier, more changeable, and more under cyclonic
control. The uniformity of the climatic conditions
over the far southem oceans is monotonously unat-
tractive. The Continental areas are small, and de-
velop to a limited degree only the more marked
seasonal and diurnal changes which are characteristic
of lands in general. The summers are less stormy
than the winters, but even the summer temperatures
are not high. Such an area as that of New Zealand,
122
CLIMATE
with its mild climate and fairly regular rains, is really
at the margins of the zone, and has, much more
favourable conditions than do the islands farther
south. These islands, in the heart of this zone, have
dull, cheerless, and inhospitable climates, with snow
sometimes in midsummer. The zone enjoys a good
reputation for healthfulness, which fact has been
ascribed chiefly to the strong and active air move-
ment, the relatively drier air than in corresponding
northern latitudes, and the cool summers. It must
be remembered, also, that the lands are mostly in the
sub-tropical belt, which possesses peculiar climate ad-
vantages, as will be seen. The northem oceans
repeat, in a much modified fora», many of the charac-
teristics of the south temperate oceans. Except to
leeward of the broad lands, the northern oceans have
the conservative features typical of ^ marine climates
the world over.
Sub-tropical Belts: Mediterranean Climates. At
the tropical margins of the temperate zones, in the
latitudes of the tropical high pressure areas, are
the so-called sub-tropical beits. Far enough from the
equator to be free from continued high temperatures,
and near enough to it to be spared the extreme cold
of higher latitudes, these transition beits are among
the most favoured of the world. Their rainfall ré-
gime is altemately that of the westerlies and of the
trades. They are thus associated, now with the tem-
perate, and now with the tropical zones. In winter,
the equatorward migration of the great pressure and
CHABACTERISTICS OF ZONES—TEMPERATE 123
wind systems brings these latitudes under the control
of the westerlies, whose frequent irregular storms
give a moderate winter precipitation. These winter
rains recall the winter trade rains of the tropics,
although their origin is different. They are not
steady and continuous, but are separated by spells of
fine, sunny weather. The amounts vary greatly.1
In summer, when the trades are extended pole-
wards by the outflowing equatorward winds on the
eastern side of the ocean highs, mild, dry, and nearly
continuous fair weather prevails, with general north-
erly winds.
The sub-tropical beits of winter rains and dry
summers are not very clearly defined. They do not
extend continuously around the world. They are
mainly limited to the western coasts of the continents,
and to the islands off these coasts, in latitudes between
about 28° and 40°. Their degree of development
and their importance vary in different longitudes.
The sub-tropical belt is exceptionally wide in the east-
em hemisphere, and reaches far inland there, em-
bracing the countries bordering on the Mediterranean
in Southern Europe and northern Africa, including
the Azores and the famous Riviera, and then extend-
ing eastward across the Dalmatian coast and the
southem part of the Balkan peninsula into Syria,
Mesopotamia, Arabia north of the tropic. Persia, and
the adjacent lands. In the great eastward extension
1 In round numbers, Lisbon has 28.60 inches; Madrid, 16.60;
Algiers, 28.15; Nice, 33.00; Rome, 29.90; Ragusa, 63.90.
124
CLIMATE
of the winter rains in this area, the development of
secondary lows over the Mediterranean Sea is an im-
portant factor. The fact that the Mediterranean
countries are so generally included in this belt has led
to the use of the name “ Mediterranean climates.”
Owing to the great irregularity of topography and
outline, the Mediterranean province embraces many
varieties of climate, but the dominant characteristics
are the mild temperatures, except on the higher ele-
vations, and the sub-tropical rains.
On the west coasts of the two Americas, the sub- '
tropical belt of winter rains is clearly seen in Cali-
fomia and in northem Chile, on the west of the coast
mountain ranges. Between the region which has rain
throughout the year from the stormy westerlies, and
the districts which are permanently arid under the
trades, there is an indefinite belt over which rains fall
in winter. In Southern Africa, which is controlled
by the high pressure areas of the South Atlantic and
South Indian oceans, the south-westem Coastal belt
has winter rains, decreasing to the north, while the
east coast and adjoining interior have summer rains,
from the south-east trade. There is sub-tropical veg-
etation on the south-east coast, and a cool, dry climate
on the south-west coast. Southern Australia is cli-
matically similar to south Africa. In summer, the
trades give rainfall on the eastern coast, which de-
creases inland. In winter, the westerlies give mod-
erate rains, chiefly on the south-westem coast.
Northern Chile, California, south-westem Australia,
CHARACTERISTICS OF ZONES—TEMPERATE 125
and the Cape province of Africa are thus all in the
sub-tropical belt.
Fig. 23. Monthly Distribution of Rainfall: Sur-tropical
Winter Rains
M: Malta. W.A: Western Australia
The sub-tropical climates follow the tropical high
pressure beits across the oceans, but they do not re-
tain their distinctive character far inland from the
west coasts of the continents (except in the Mediter-
ranean case), nor on the east coasts. On the latter,
summer monsoons and the occurrence of general sum-
mer rains interfere, as in eastern Asia and in Florida,
and to some extent in South America east of the
Andes.
Strictly winter rains, with a maximum in Decem-
ber or in June, according to the hemisphere, are typi-
126
CLIMATE
cal of the coasts and islands of this belt. The more
Continental areas have a tendency to spring and
autumn rains. The rainy and dry seasons are most
marked at the equatorward margins of the belt, and
thus recall the tropical characteristic of dry and wet,
rather than cold and hot seasons. With increasing
latitude, the rain is more evenly distributed through
the year, the summer becoming more and more rainy
until, in the Continental interiors of the higher lati-
tudes, the summer becomes the season of maximum
rainfall. The monthly distribution of rainfall in two
sub-tropical regions is shown in the accompanying
data and curves (see Fig. 28).
ANNUAL MABCH OF RAINFALL! SUB-TROPICAL TYPE (in thoUS-
andths of the annual mean).
Southern Italy
Western Sicily
Australia Malta
Latitude............................. 32.3° S. About 38° N.
January............................... 14 130
February.............................. 18 93
March................................. 30 98
April................................. 64 75
May...................................150 35
June..................................183 23
July..................................168 8
August................................166 28
September............................. 93 73
October............................... 59 133
November.............................. 32 144
December.............................. 23 160
The following table (from Supan), giving the sea-
sonal distribution of rainfall in Southern Europe, in
CHARACTERISTICS OF ZONES—TEMPERATE 127
percentages of the annual mean, shows very clearly
the change in the rainfall season in going from north
to south. In the northem Tyrol, the normal type of
central Europe prevails. In Sicily, the summer is
almost rainless: the sub-tropical type is fully
developed.
SEASONAL DISTRIBUTION OF RAINFALL IN CENTRAL AND SOUTH-
ERN europe (in percentages of the annual mean).
Winter Spring Summer Autumn
Northern Tyrol 16 24 37 23
Southem Tyrol 14 26 28 32
Po Valley 20 26 24 30
Central Italy 25 24 17 34
Southem Italy 31 25 11 33
Sicily 39 22 3 36
Malta 48 14 2 36
In Alexandria the dry season lasts nearly eight
months; in Palestine, from six to seven months; in
Greece, about four months.
The sub-tropical rains are peculiarly well developed
on the eastern coast of the Atlantic Ocean, and are
clearly illustrated in the accompanying diagram,
after Supan (see Fig. 24).
The different types of rainfall are as follows:
I. North of lat. 40° N. Rain throughout the year.
II. Lats. 40°_27° N. Dry in summer (sub-tropical
rains).
III. Lats. 27°-19° N. Always deficiënt in rainfall.
IV. Lats. 19°-7° N. Dry in winter (tropical
rains).
V. Lats. 7°-l° N. Always rainy (equatorial belt).
128
CLIMATE
VI. Lats. 1° N.-17° S. Dry in winter (tropical rains).
VII. Lats. 17°-30° 8. Always dry.
VIII. Beyond lat. 30° S. Dry in summer (sub-tropical
rains).
(IX. Always rainy on the oceans. The African west
coast does not extend into this zone.)
50W
40
30
ZO
10
0
m
20
30
Winter Summer
I
II
m
w
v
vi
m
| m
Summer Winter
Fig. 24. Rainy and Rainless Zones on
Eastern Atlantic Coast
The winter rains which migrate equatorward are
separated by the Sahara from the equatorial rains
which migrate poleward. An unusually extended
migration of either of these rain beits may bring them
CHARACTERISTICS OF ZONES—TEMPERATE 129
close together, leaving but a small part, if any, of the
intervening desert actually rainless. The Arabian
desert occupies a somewhat similar position. Large
variations in the annual rainfall, and droughts, may
be expected towards the equatorial margins of the
sub-tropical beits. Irrigation is practised in many
places.
TABLB OF MEAN MONTHLY TEMPERATURES FOR SELECTED SUB-
TROPICAL STATIONS.1
Continental Insular
Bagdad Cordoba Bermuda Auckland
Lat. 33°19' N. 31°25' S. 32°20' N. 36°50' N.
Long. 44°26' E. 64°12' W. 64°43' W. 174°51' E.
Altitude 39 ft. 1440 ft. 148 ft. 276 ft.
January 50.9° 73.4° 62.4° 67.1°
February 53.1 72.3 61.9 67.5
March 62.1 68.4 61.7 65.5
April 69.3 61.0 64.4 61.5
May 82.0 54.5 69.6 56.7
June 89.6 49.1 74.8 53.2
July 92.8 50.0 78.8 51.8
August 92.7 54.3 80.1 52.2
September 85.6 58.6 78.1 54.5
October 76.5 63.5 73.4 57.4
November 62.1 68.5 67.6 60.3
December 52.5 71.8 63.7 64.8
Mean 72.4 62.1 69.7 59.4
Range 41.9 24.3 18.4 15.7
The main features of the sub-tropical rains east of
the Atlantic are repeated on the Pacific coasts of the
1 Given to nearest tenth of a degree Fahr.
9
m
CLIMATE
two Americas. In North America, the rainfall de-
creases from Alaska, Washington, and northern Ore-
gon southwards to Lower California, and the length
of the summer dry season increases. The mean an-
nual rainfall (1871-1901) at Neah Bay, Wash., is
112.40 inches; at San Francisco, Cal., 22.88 inches,
and at San Diego, Cal., 9.40 inches. At San Diego,
six months (May-October) have each less than five
per cent. of the annual precipitation, and four of
these have one per cent. The southem extremity of
Chile, from about latitude 88° S. southward, has
heavy rainfall throughout the year from the wester-
lies, with a winter maximum. Northem Chile is per-
sistently dry. In the intermediate area there are
winter rains and dry summers. Neither Africa nor
Australia extends far enough south to show the dif-
ferent members of this system well. New Zealand
is almost wholly in the prevailing westerly belt.
Northem India is unique in having summer monsoon
rains, and also winter rains from weak cyclonic
storms, which correspond to the sub-tropical winter
rains.
From the position of the sub-tropical beits to lee-
ward of the oceans, and at the equatorial margins of
the temperate zones, it follows that their temperatures
are not extreme. Further, the protection afforded
by mountain ranges, as by the Alps in Europe and
the Siërra Nevada in the United States, is an im-
portant factor in keeping out extremes of winter cold.
The annual march, and ranges, of temperature de-
CHARACTERISTICS OF ZONES—TEMPERATE 131
pend upon position with reference to Continental or
marine influences. This is seen in the accompanying
data and curves for Bagdad, Cordoba, Bermuda, and
Auckland (see Fig. 25).
Fig. 25. Annual March of Temperature for
Selected Sub-tropical Stations
Bd: Bagdad. Ba: Bermuda. A: Auckland.
C: Cordoba
Autumn is, as a rule, a good deal warmer than
spring, as in all the eastern Mediterranean basin, the
Canaries, and Madeira. This basin is particularly
132
CLIMATE
favoured in winter, not only in the protection against
cold afforded by the mountains, but also in the high
temperature of the sea itself. The Southern Alpine
valleys and the Riviera are well situated, having good
protection and a Southern exposure. The coldest
month usually has a mean temperature well above
82°. Mean minimum temperatures of about, and
somewhat below, freezing occur in the northem por-
tion of the district,1 and in the more Continental lo-
calities minima a good deal lower have been observed.
(At San Diego, Cal., the absolute minimum is 82°;
at San Francisco, 29°.) Mean maximum tempera-
tures of about 95° occur in northem Italy, and of
still higher degrees in the southem portions. Some-
what similar conditions exist in the sub-tropical
district of North America. Under the control of
passing cyclonic storm areas, hot or cold winds, which
often owe some of their special characteristics to the
topography, bring into the sub-tropical beits, from
higher or lower latitudes, unseasonably low or high
temperatures. These winds have been given special
names (mistral, sirocco, bora, chamsin, leste, leveche,
pampero, southerly burster, etc.)
These beits enjoy abundant sunshine, being among
the least cloudy districts in the world. The accom-
panying data and curve, giving an average for ten
stations, show the small annual amount of cloud, the
winter maximum and the marked summer minimum,
in a typical sub-tropical climate. (Fig. 26).
i Nice, 30.4°; Rome, 25.7°; Palermo, 32°; Athens, 28.8°.
CHARACTERISTICS OF ZONES—TEMPERATE 133
MONTHLY DISTRIBUTION OP CLOUDINESS IN A SUB-TROPICAL
CLIMATE (EASTERN MEDITERRANEAN, LAT. 33.8° N.)
Jan. Feb. Mar. Apr. May June July Aug. Sept. Oct. Nov. Dec. Year
4.9 4.6 3.8 3.7 2.8 1.3 1.1 1.3 1.8 2.5 4.0 4.7 3.0
The winter rains do not bring continuously over-
cast skies; and it has been well said that the problem
of securing a maximum rainfall with a maximum
number of clear days has been solved on the southem
Alpine slopes. A summer month with a mean
10
9
8
7
6
5
4
3
2
I
0
Fig. 26. Annual March of Cloudiness in a Sub-tropical Climate
(Eastern Mediterranean)
cloudiness of 0.1 is not exceptional in the drier parts
of the sub-tropics. The winter cloudiness in northem
Italy is 5.0 to 6.0; in summer, 8.0 to 4.0. Cairo
has an annual mean of 1.9, and in June it has
0.8. Biskra, on the northem margin of the Sahara,
has 264 clear days. In the central valley of Cali-
134
CLIMATE
fornia, the number of clear days is similarly very
large.
With prevailingly fair skies, even temperatures, and
moderate rainfall, the sub-tropical beits possess many
climatic advantages which fit them for health resorts.
The long list of well-known resorts on the Mediter-
ranean coast, and the shorter list for Califomia, bear
witness to this fact.
North Temperate Zone: Weet Coaete. Marine
climatic types are carried by the prevailing wester-
lies on to the western coasts of the continents, giving
them mild winters and cool summers, abundant rain-
fall and a high degree of cloudiness and relative
humidity. North-western Europe is particularly
favoured because of the remarkably high tempera-
tures of the North Atlantic Ocean, and because of the
influence of the winds controlled by the low pressure
area off Iceland. In January, north-western Europe
has temperatures from 20° to 40° in excess of the
normal for the latitude. The north-western coast of
North America has temperatures more than 10° too
warm for the latitude. January means of 40° to 50°
in the British Isles and on the northem French coast
occur in the same latitudes as those of 0° and 10° in
the far interior of Asia. In July, means of 60° to
70° in the former contrast with 70° and 80° in the lat-
ter districts. The conditions are somewhat similar
in North America. Along the western coasts of
North America and of Europe the mean annual
ranges are under 25°,—actually no greater than some
Fig. 27. annual March op
Temperature for Selected
Stations in the Temperate
Zones
-
S. I: Scilly Isles. P: Prague. C:
Charcow. S: Semipalatinsk. K;
Kiakhta. B: Blagoweschtschensk.
Sa: Sakhaliu. T: Thorshavn.
Y: Yakutsk
135
13$
CLIMATE
of those within the tropics.. Irregular cyclonic tem-
perature changes are, however, marked in the tem-
perate zone, while absent in the tropics. The data
and curves for the Scilly Isles and for Thorshavn,
Faroe Islands, illustrate the insular type of temper-
ature on the west coasts (see Fig. 27). In the
Faroes the mean maximum is 65.1°, and the mean
minimum 16°. It will be noted that the poleward
decrease in the mean annual and the mean winter
temperatures is very slow between latitudes 50° and
62° N. on the west coast of Europe.
TABLB OF MBAN MONTHLY TBMPEBATUBBg FOB 8BLBCTBD STA-
TIONS IN THE TEMPERATE ZONES.
Along lat. 60° N. At lat. 62°N.
West Coast Continental Bast Coast Insular Conti- nental
Scilly Isles Prague Charcow Semi- pala- tinsk Kiakh- ta Blago- wescht- schensk Sakha- lin Thors- havn, Faroe Isles Yakutsk, B.Si- beria
Lat. 49°55' 50°5/ SO*^ 50°24' 50°21' 50° 15' 50°50' 62°2' 62°1'
Long. 6°20' W. 14°26' E. 36°11' 80°13' 106°31' 127°38' 142°7' E. 6°44' W. 129°43'E
Alt. (ft.) 98.4 662.7 413.4 593.8 2526 360.9 180.4 29.5 328.1
Jan. 45.7° 29.8° 16.5° 0.5° -15.9° -13.9° -0.4° 37.8° -45.2°
Peb. 45.7 32.0 22.1 1.8 -5.4 -3.3 5.0 38.1 -35.0
March 46.0 37.8 29.3 14.4 16.9 14.4 15.8 37.8 -10.7
April 48.7 47.3 44.8 38.3 34.3 34.7 31.1 41.9 15.1
May 52.5 55.9 58.8 57.2 48.7 49.6 41.4 45.0 40.3
June 57.9 63.3 65.1 68.0 63.1 63.7 50.7 49.5 58.5
July 60.8 66.7 69.6 72.0 66.4 70.5 60.3 51.4 65.8
Aug. 61.2 65.3 66.4 67.3 61.7 65.8 62.2 51.3 59.7
Sept. 58.6 58.8 56.1 54.9 48.0 53.2 53.6 48.7 42.3
Oct. 54.0 48.7 45.5 38.1 32.0 34.2 39.6 43.9 15.8
Nov. 49.6 37.6 33.8 20.1 11.8 9.7 22.5 40.6 -21.3
Dec. 47.3 31.3 23.2 6.1 -2.7 -9.2 7.3 38.1 -41.1
Year 52.3 47.9 44.3 36.5 29.9 30.8 32.4 43.7 12.0
Range 15.5 36.9 53.1 71.5 82.3 84.4 62.6 13.6 111.0
CHARACTERISTICS OF ZONES—TEMPERATE 137
MONTHLY DISTRIBUTION OF RAINFALL (IN THOUSANDTHS OF
THE ANNUAL MEAN). TEMPERATE ZONE.
Continental Summer Rains Coast Rains
Moderate Very heavy Uniform Distribution Fall and Winter Rains
Central Europe North of Alps Northern Asia Atlantic Coast, North America North-west Europe
Lat. About 50° N. About 55° N. About 40° N. About 60° N.
January 57 20 84 100
February 56 17 77 80
March 68 18 85 72
April 71 35 70 56
May 92 75 80 58
June 115 235 81 64
July 121 215 96 * 70
August 117 122 87 80
September 82 133 84 102
October* 75 58 91 110
November 74 40 86 102
December 72 32 79 106
The monthly distribution of rainfall, with the
marked maximum in the fall and winter which is
characteristic of the marine régime, is illustrated in
the last column of the table above, for north-western
Europe, and in the corresponding curve (see Fig.
28).
On the northem Pacific coast of North America,
the distribution is similar. Thus at Olympia, Wash-
ington, there is a distinct cold season maximum, as
appears in the following data:
138
CLIMATE
MONTHLY DISTBIBUTION OF RAINFALL AT OLYMPIA, WASHING-
TON (IN THOUSANDTHS OF THE) ANNUAL MEAN).
January .......................................159
February ......................................135
March ......................................... 95
April ..........................................65
May ........................................... 44
June ...........................................31
July .......................................... 13
August ........................................ 13
September ..................................... 53
October ....................................... 86
November ......................................124
December ......................................182
In the southem hemisphere, the western coasts of
southem South America, Tasmania, and New Zea-
land show the same type.
The cloudiness and relative humidity average high
on western coasts, with the maximum in the colder
season. The difference in general rainfall conditions
between the west coast, typified by the exaggerated
case of Valentia, in south-westem Ireland, and the
Mediterranean, is seen in the number of rainy days
in each district. Valentia has nearly 250. In the
Mediterranean, they may be set down as about 100,
in round numbers.
The west coasts, therefore, including the important
climatic province of western Europe, and the coast
provinces of north-western North America, New
Zealand, and Southern Chile, have, as a whole, mild
winters, equable temperatures, small ranges, and
CHARACTERISTICS OF ZONES—TEMPERATE 139
abundant rainfall, fairly well distributed through the
year. The summers are relatively cool, especially on
the Chilean coast.
Fig. 28. Annual March of Rainfall: Temperate Zones
C. E: Central Europe. A: Northern Asia. N. A: Atlantic Coast of
North America, N. W.E: Northwest Europe
Continental Interiors. The equable climate of the
western coasts changes, gradually or suddenly, into
the more extreme climates of the interiors. In
Europe, where no high mountain ranges intervene,
140
CLIMATE
the transition is gradual, and broad stretches of coun-
try have the benefits of the tempering influence of the
Atlantic. In North America, the change is abrupt,
and comes on Crossing the lofty western mountain
barrier. The data in the table on page 186, and the
corresponding curves in Fig. 27, illustrate well the
gradually increasing severity of the climate with in-
creasing distance inland in Eurasia. Central Europe
is seen to lie between the modified marine climate of
the west coast and the Continental conditions of
Russia and Siberia. Its mean temperatures do not
differ very much from those on the coast, but the
seasons are more sharply contrasted.
The Continental interiors of the north temperate
zone have the greatest extremes in the world. To-
wards the Arctic circle, the winters are extremely se-
vere, and January mean temperatures of —10° and
—20° occur over considerable areas. At the cold pole
of northem Siberia a January mean of —60° is found.
Mean minimum temperatures of —40° occur in the
area from eastern Russia, over Siberia and down to
about latitude 50° N. At Verkhoyansk, an im-
portant town just beyond the Arctic circle, the ab-
solute minimum is below —90°. Over no small part
of Siberia minimum temperatures below —70° may
be looked for every winter. Thorshavn and Yak-
utsk (see table on page 186) are excellent examples
of the temperature differences along the same lati-
tude line. The winter in this interior region is domi-
nated by a marked high pressure. The weather is
CHARACTERISTICS OF ZONES—TEMPERATE UI
prevailingly clear and calm. The ground below a
slight depth is frozen the year around, over wide
areas. The moderate snowfall is sufficiënt, with the
continued cold, to make sleighing possible for im-
mense stretches all over the country. The frozen
rivers can be crossed without bridges. This unifying
influence, of easy winter communication, has been
most important in Russian history, as Leroy-Beau-
lieu has pointed out. The extremely low tempera-
tures are not disagreeable except when the steppes
are swept by icy storm winds (buran, purga),
carrying loose snow, and often resulting in loss of
life.
In the North American interior, the winter cold is
somewhat less severe. The lowest January mean
temperatures are —80°, in the extreme northem por-
tion of the continent. Mean annual minima of —40°
occur down into the northern interior portion of the
United States. The lowest is about —60°, near Great
Bear Lake, with an absolute minimum of about —72°.
North American winter weather in middle latitudes
is often interrupted by cyclones, which, under the
steep poleward temperature gradiënt then prevail-
ing, cause frequent, marked, and sudden changes in
wind direction and temperature over the central and
eastern United States. Cold waves and warm waves
are common, and blizzards resemble the buran or
purga of Russia and Siberia. With cold northerly
winds, temperatures below freezing are carried far
south towards the tropic. The January mean tem-
142
CLIMATE
peratures in the southem portions of the Continental
interiors average about 50° or 60°.
In summer, the northern Continental interiors are
warm, with July means of 60° and thereabout.
These temperatures are not much higher than those
on the west coasts, but as the northem interior win-
ters are much colder than those on the coasts, the in-
terior ranges are very large. The mean annual
extreme ranges exceed 150° in northem North
America and 170° in Siberia. Mean maximum tem-
peratures of 85° occur beyond the Arctic circle in
north-eastern Siberia, and beyond latitude 60° in
North America. In spite of the extreme winter cold,
agriculture extends remarkably far north in these
regions, because of the warm, though short, summers,
with favourable rainfall distribution. The July
isotherm of 50° is about the northem limit of tree
growth. Beyond a zone of stunted tree growth,
comes the tundra. The summer heat is sufficiënt to
thaw the upper surface of the frozen ground, and
vegetation prospers for its short season. At this
time, great stretches of flat surface become swamps.
The southem interiors have torrid beat in summer,
temperatures of over 90° being recorded in the south-
western United States and in southem Asia. In
these districts the diurnal ranges of temperature are
very large, often exceeding 40°, and the mean
maxima exceed 110°.
In South America, the interior of Argentina has
moderate mean annual ranges (20°-80°); the mean
CHARACTERISTICS OF ZONES—TEMPERATE 143
maxima reach 95°—100° and even higher, and the
mean minima fall below 23°. The west coast has
smaller ranges (less than 20°); lower mean maxima
(77°-86°), and higher mean minima (32°-23°).
The winter maximum rainfall of the west coasts
becomes a summer maximum in the interiors. The
change is gradual in Europe, as is the change in tem-
perature, but more sudden in North America. The
curves for central Europe and for northem Asia (see
Fig. 28) illustrate these Continental summer rains.
The summer maximum becomes more marked with
the increasing Continental character of the climate.
Thus, while June to August in central Europe supply
about thirty-five per cent. of the annual precipita-
tion, in northem Asia, excluding the coast, they give
nearly sixty per cent. The rains of Asia are actually
comparable, in relative intensity, at their maximum,
with the rains of the tropics. In Bengal, e. g., June
to August give only fifty-seven per cent. of the
annual rainfall. The winter dry season of Asia is,
however, very different from a tropical dry season, be-
cause of the difference in conditions of vegetation and
of snow cover. In North America, Nebraska, a state
which is typical of a considerable district of summer
rains, receives about sixty per cent. of the annual
rainfall in the months of April, May, June, and
July.
The change in rainfall season with increasing dis-
tance from the Atlantic Ocean in Eurasia is well
brought out by Supan in the following table:
144
CLIMATE
TABLE SHOWING SEASONAL DISTRIBUTION OF RAINFALL IN
EURA8IA (IN PERCENTAGES OF THE ANNUAL MEAN).
Winter Spring Summer Autumn
Ireland 28 21 24 27
Western England 28 19 24 29
Eastern England 23 19 28 30
North-western Germany 23 22 31 24
Central Germany 20 23 34 23
Eastern Germany 19 22 37 22
Western Russia 16 21 39 24
Central Russia 16 22 37 25
Western Siberia 13 13 42 32
Eastern Siberia 9 12 58 21
There is also a well-marked decrease in the amount
of rainfall inland. In western Europe, the rainfall
averages 20-30 inches, with much larger amounts
(reaching 80-100 inches and even more) on the
bold west coasts, as in the British Isles and Scan-
dinavia, where the moist Atlantic winds are deflected
upwards, and also locally on mountain ranges, as on
the Alps. There are small rainfalls (below 20
inches) in eastern Scandinavia and on the Iberian
peninsula. Eastern Europe has generally less than
20 inches; western Siberia about 15 inches, and east-
em Siberia about 10 inches. In the Southern
part of the great overgrown continent of Asia, an ex-
tended region of steppes and deserts, too far from
the sea to receive sufficiënt precipitation, shut in by
mountains, and controlled in summer by drying
northerly winds, receives less than 10 inches a year,
and in places less than 5 inches. In this interior
district of Asia, population is inevitably small, and
suffers under a condition of hopeless aridity.
CHARACTERISTICS OF ZONES—TEMPERATE 145
The North American interior has more favourable
rainfall conditions than Asia, because the former
continent is narrower. The heavy rainfalls on the
western slopes of the Pacific coast mountains
correspond, in a general way, to those on the west
coast of Europe, although they are heavier (over 100
inches at a maximum). The close proximity of the
mountains to the Pacific, however, involves a much
more rapid decrease of rainfall inland than is the case
in Europe, as may be seen by comparing the isohyetal
lines in the two cases. The rain-shadow influence of
the Pacific coast Cordilleras extends about half-way
across the continent. A considerable interior region
is left with deficiënt rainfall (less than 10 inches) in
the south-west. The eastern portion of the continent
is freely open to the Atlantic and the Gulf of Mexico,
so that moist cyclonic winds have free access, and
rainfalls of over 20 inches are found everywhere east
of the lOOth meridian. These conditions are much
more favourable than those in eastern Asia. The
greater part of the interior of North America has the
usual warm-season rains. In the interior basin, be-
twèen the Rocky and Siërra Nevada mountains, the
higher plateaus and mountains receive much more
rain than the desert lowlands. Forests grow on the
higher elevations, while irrigation is necessary for
agriculture on the lowlands. The rainfall here comes
chiefly from thunder-storms.
In southem South America, the narrow Pacific
slope has heavy rainfall (over 80 inches). East of
io
146
CLIMATE
the Andes the plains are dry (mostly less than 10
inches). The Southern part of the continent is very
narrow, and is ópen to the east. It is also more open
to the west than is the country farther north, owing
to the decreasing height of the mountains southward.
Hence the rainfall increases somewhat to the south,
coming in connection with passing cyclones. Tas-
mania and New Zealand have most rain on their
western slopes.
In a typical Continental climate, the winter, except
for radiation fogs, is very clear, and the summer is
the cloudiest season, as is well shown in the follow-
ing data and curve for eastern Asia. In a more
moderate Continental climate, such as that of central
Europe, and much of the United States, the winter
is the cloudiest season (see Fig. 29).
MONTHLY DISTRIBUTION OF CLOUDINE88 IN CONTINENTAL
CLIMATES.
I. Eastern Asia. 10 stations. Lat. 56.5° N. Long. 115° E.
Jan. Feb. Mar. Apr. May June July Aug. Sept. Oct. Nov. Dec. Year.
3.1 3.4 3.9 4.7 5.7 5.6 6.2 6.0 5.5 5.4 4.8 4.2 4.9
II. Central Europe. Hnngarian Plain. Lat 47° N.
Jan. Feb. Mar. Apr. May June July Aug. Sept. Oct. Nov. Dec. Year.
6.5 5.9 5.7 5.6 5.4 5.3 4.4 4.2 4.6 5.8 6.6 6.9 5.6
In the first case, the mean cloudiness is small; in
the second, there is a good deal of cloud all the year
around.
The vast Continental interiors, whose climatic
features have here been outlined, can obviously be
CHARACTERISTICS OF ZONES—TEMPERATE 147
subdivided into smaller climatic provinces almost
indefinitely, as pointed out in Chapter III.
Fig. 29. Annual March op Cloudiness in Continental and
Mountain Climates: Temperate Zones.
£ : Central Europe. A : Eastern Asia. M : Mountain
East Coasts. The prevailing winds carry the ma-
rine climate of the oceans on to the western coasts of
the temperate zone lands. They also carry the Con-
tinental climates of the interiors off over the eastern
coasts of these same lands, and even for some distance
on to the adjacent oceans. The east coasts, therefore,
have Continental climates, with modifications result-
ing from the presence of the oceans to leeward, and
are necessarily separated from the west coasts, with
which they have little in common. On the west coasts
of the north temperate lands the isotherms are far
apart. On the east coasts, they are crowded together.
The east coasts share with the interiors large annual
148
CLIMATE
and cyclonic ranges of temperature. At latitude 55°
N., for example, the east coast of Asia has a mean
annual range which is four times as large as that of
the west coast. A glance at the isothermal maps of
the world will show at once how favoured, because
of its position to leeward of the warm North Atlantic
waters, is western Europe as compared with eastern
North America. A similar contrast, less marked, is
seen in eastern Asia and western North America.
In eastern Asia, there is some protection, by the coast
mountains, against the extreme cold of the interior,
but in North America there is no such barrier, and
severe cold winds sweep across the Atlantic coast
States, even far to the south. Owing to the prevail-
ing offshore winds, the oceans to leeward have rela-
tively little effect. In the north-east, the cold water
is effective in giving cooler summers than farther
south.
As already noted, the rainfall increases from the
interiors towards the east coasts. In North America,
the distribution through the year is very uniform,
with some tendency to a . summer maximum, as in the
interior (see Fig. 28).
In eastern Asia the winters are relatively dry and
clear, under the influence of the cold offshore mon-
soon, and the summers are warm and rainy, with the
northward extension of the south-east monsoon, which
reaches as far as lat. 60° N. The summer maximum
of rainfall on this coast is clearly shown in the follow-
ing data (Trabert):
CHARACTERISTICS OF ZOU ES—TEMPERATE 149
MONTHLY DISTRIBUTION OF RAINFALL. EAST COAST OF ASIA.
(IN PERCENTAGES OF ANNUAL mean).
Jan. Feb. Mar. Apr. May June July Aug. Sept. Oct. Nov. Dec. Year.
2 2 3 6 8 10 12 21 16 11 6 3 19.3 ins.
-
Rainfalls of 40 inches are found on the east
coasts of Korea, Kamchatka, and Japan, while in
North America, which is more open, they reach
farther inland. Japan, although occupying an in-
sular position, has a modified Continental, rather than
a marine climate. The winter monsoon, after Cross-
ing the water, gives abundant rain on the western
coast, while the winter is relatively dry on the lee of
the mountains, on the east. Japan has smaller tem-
perature ranges than the mainland.
Mountain Climates. The mountain climates of
the temperate zone have the usual characteristics
which are associated with altitude everywhere. If
the altitude is sufficiently great, the decreased tem-
perature gives mountains a polar climate, with the
difference that the summers are relatively cool, while
the winters are mild, owing to inversions of tempera-
ture in anticyclonic weather. Hence the annual
ranges are smaller than over lowlands. At such
times of inversion, the mountain tops often appear
as local areas of higher temperatures in a general
region of colder air over the valleys and lowlands.
The increased intensity of insolation aloft is an im-
portant factor in giving certain mountain resorts
their deserved popularity in winter {e. g., Davos and
150
CLIMATE
Meran). Of Meran it has been well said that from
December to March the nights are winter, but the
days are mild spring. Mountains provoke rainfall,
even in arid Continental interiors, and thus we have
well-forested plateaus and mountain slopes rising
above desert lowlands. The diurnal ascending air
currents of summer usually give mountains their
maximum cloudiness and highest relative humidity
in the warmer months, while winter is the drier and
clearer season. This is shown in the data below (see
Fig. 29).
MONTHLY DISTRIBUTION OP CLOUDINESS. MOUNTAIN CLIMATE. ’
(CENTRAL EUROPE. ALPINE SU M MITS. 8500 FT. LAT. 47° N.
BEVEN STATIONS.)
Jan. Feb. Mar. Apr. May June July Aug. Sept. Oct. Nov. Dec. Year.
5.0 5.3 6.0 6.5 7.0 6.7 6.1 5.8 6.0 6.0 5.5 5.1 5.0
The clouds of winter are low; those of summer
are higher. Hence the annual march of cloudiness
on mountains is usually the opposite of that on
lowlands.
CHAPTER VI
THE CHABACTERISTICS OF THE ZONES: III.—THE
POLAR ZONES
General: Relation to Man, Animale, and Plants—Temperature—
Pressure and Winds—Rain and Snow—Humidity, Cloudiness,
and Fog—Cyclones and Weather—Twilight and Optical
Phenomena—Physiological Effects.
General: Relation to Man, Animale, and Plant».
The temperate zones merge into the polar zones at
the Arctic and Antarctic circles or, if temperature
is used as the basis of classification, at the isotherms
of 50° for the warmest month, as suggested by Su-
pan. The frequent use of maps on the Mercator
projection tends to give us an exaggerated idea of
the size of the polar zones. When limited by the polar
circles, these zones occupy but 0.08 of the surface of
each hemisphere, the whole area being 1.00. As-
tronomically they are distinguished by the fact that
at all places within them the sun is above the horizon
at least one full twenty-four hours each year, and be-
low it the same length of time. This longer or shorter
absence of the sun gives the climate a peculiar char-
acter, not found elsewhere. At the poles, the day
152
CLIMATE
and the year are alike. These zones obviously have
the most oblique insolation.
For but a very small part of the polar zones have
we any knowledge, by observation, of the climate.
The fragmentary records of the earlier expeditions
gave scattering information about the weather. The
longer and more complete records of recent expedi-
tions give much more accurate and satisfactory re-
sults. It is now becoming possible to see more clearly
what the climatic conditions really are. But as yet
no scientific presentation of polar climatology is pos-
sible. We are still dealing with the meteorology of
the polar zones, rather than with their climates. More
is known of the Arctic than of the Antarctic. From
the latter there are already several excellent con-
tributions, but up to this time no record both as long
and as complete as that of the Nansen Expedition
has been obtained. The admirable report, by Dr.
Mohn, on the results of this expedition, embracing
three years’ observations, discussed with great care,
and well illustrated by curves and charts, is a monu-
mental piece of work. Under the able directorship of
Mr. Walter G. Davis, however, the Argentine Me-
teorological Service is steadily accumulating observa-
tions at its far Southern stations, on the South Orkney
and South Shetland Islands, and although these sta-
tions are not within the Antarctic zone, they will fur-
nish valuable information concerning the great ocean
area surrounding this zone.
Beyond the isotherm of 50° for the warmest month,
CHARACTERISTICS OF ZONES—POLAR 153
forest trees and cereals do not grow. In the northern
hemisphere this line is well north of the Arctic circle
in the Continental climate of Asia, and north of it in
north-western North America. It is north of it also
in northem Scandinavia, but falls well south in east-
em British America, Labrador, and Greenland, and
also in the North Pacific Ocean. In the southem
hemisphere this isotherm crosses the southem extrem-
ity of South America, and runs nearly east and west
around the globe.
In the Arctic climate, vegetation must make rapid
growth in the short, cool summer. In the highest
latitudes the summer temperatures are not high
enough to melt snow on a level. Exposure is there-
fore of the greatest importance. Arctic plants grow
and blossom with great rapidity and luxuriance where
the exposure is favourable, and where the water from
the melting snow can run off. The soil then dries
quickly, and can be efïectively warmed. On the
other hand, when the water stands, it may freeze again
and again, and the soil undemeath has no oppor-
tunity to warm. Of Novaya Zemlya^Baer has re-
ported that the level surfaces are polar deserts, while
the slopes at the foot of the mountains, unless covered
with boulders, are like gardens in summer. Protec-
tion against cold winds is another important factor in
the growth of this vegetation. Over great stretches
of the northern plains the surface only is thawed out
in the warmer months, and swamps, mosses, and
lichens are found above etemally frozen ground.
154
CLIMATE
Trees often grow in favourable conditions along
streams when the intervening plains are typical
tundras. Direct insolation is very effective in high
latitudes. Where the exposure is favourable, snow
melts in the sun even when the temperature of the air
in the shade is far below freezing. It has been re-
ported that at Assistance Bay (lat. 74^>° N.), in
March, when the air temperature was about —25°,
snow near stones and other dark objects melted in the
sun. Even the mean daily temperature of the snow
surface may he higher than the air temperature. The
injurious effect of polar climate upon vegetation,
especially upon trees, has been attributed by Kihl-
mann to an insufficiënt water-supply furnished hy
the roots deep in the cold ground. From the upper
parts of the tree, exposed to sunshine and wind, evap-
oration proceeds rapidly, and the tree dries up.
Protective devices against excessive evaporation, not
unlike those of desert plants, are found.
Arctic and Antarctic zones differ a good deal in
the distribution and arrangement of land and water
around and in them. The southem zone is sur-
rounded by a wide belt of open sea; the northem, by
land areas. The northem is therefore much affected
by the conditions of adjacent Continental masses.
Nevertheless, the general characteristics are appar-
ently much the same over both, so far as is now
known, the Antarctic differing from the Arctic
chiefly in having colder summers, and in the regularity
of its pressure and winds. The cold Antarctic sum-
CHARACTERISTICS OF ZONES—POLAR 155
mers are the chief cause of the poverty of the Antarc-
tic flora. Both zones have the lowest mean annual
temperatures in their respective hemispheres, and
hence may properly be called the cold zones.
Temperature. At the solstices, the two poles re-
ceive the largest amounts of insolation which any part
of the earth’s surface ever receives. It would seem,
therefore, that the polar temperatures should then be
the highest in the world, but as a matter of fact they
156
CLIMATE
are nearly or quite the lowest. Temperatures do not
follow insolation in this case because much of the lat-
ter never reaches the earth’s surface; because most
Fig. 31. July North Polar Isotherms
of the energy which does reach the surface is ex-
pended in melting the snow and ice of the polar areas;
and also because the water areas are large, and the
duration of insolation is short. Hence the mean
annual temperatures at both poles are nearly, or
quite, the lowest in the world.
CHARACTERISTICS OF ZONES—POLAR 157
A set of monthly isothermal charts of the north
polar area, based on all available observations, was
prepared by Mohn and published in the volume on
Meteorology of the Nansen Expedition. These
charts give the most authentic information now at
hand regarding Arctic temperatures. In the winter
months there are three cold poles, in Siberia, in
Greenland, and at the pole itself. In January, the
mean temperatures at these .three cold poles are —49°,
—40°, and —40° respectively.
The Siberian cold pole becomes a maximum of tem-
perature during the summer, but the Greenland and
polar minima remain throughout the year. In April
the lowest isotherm, — 22°, is in Greenland, and the
north pole is then within the area enclosed by —18.4°.
In July the temperature distribution shows consider-
able uniformity; the gradients are relatively weak.
A large area in the interior of Greenland, and one
of about equal extent around the pole, are within the
isotherm of 82°. Hence the statement frequently
made, that no places in the northem hemisphere have
mean temperatures below freezing in July, is not cor-
rect. In October the interior of Greenland is en-
closed by —18°, and at the pole we find —11.2°. For
the year a large area around the pole is enclosed by
the isotherm of —4°, with an isotherm of the same
value in the interior of Greenland, but a local area
of — 7.6° is noted in Greenland, and one of —11.2° is
centred at lat. 85° N. and long. 170° E. It 'will be
seen that the temperatures are relatively lower to-
158
CLIMATE
wards the eastern sides of the great continents. The
ordinary mean annual isothermal chart shows, within
the Arctic circle, temperatures of 40° off the Nor-
wegian coast and — 5° beyond lat. 75° N., north of
Fig. 32. Mean Annual North Polar Isotherms
Asia and North America. The January chart shows
80° off the Norwegian coast, and — 60° at Verkho-
yansk, in Siberia. The July chart shows 60° over the
continents, to 40° in extreme north-eastem Asia.
CHARACTERISTICS OF ZONES—POLAR 159
The north polar chart of annual range of tempera-
ture shows a maximum range of about 120° in Siberia;
of 80° in North America; of 75.6° at the north pole,
and of 72° in Greenland. The north pole obviously
has a Continental climate. The minimum ranges are
on the Atlantic and Pacific oceans. The mean an-
nual isanomalies show that the line of zero anomaly
passes through the pole (as it must do). The in-
terior of Greenland has a negative anomaly in all
months. The Norwegian sea area is 45° too warm in
January and February. Siberia has +10.8° in sum-
mer, and — 45° in January. Between Bering Strait
and the pole there is a negative anomaly in all months.
The influence of the Gulf Stream drift is clearly seen
on this chart, as it is also on that of mean annual
ranges.
The mean temperatures of the higher northern
latitudes in January, July, and for the year have been
determined by Mohn with the following result:
MEAN TEMPERATURES OF THE HIGHER NORTHERN LATITUDES.
1 60° 65° 70° 75° 80° 85°
Jan. + 3.0° -9.4° -15.3° -20.2° -26.0° -36.6°
July 57.4 54.3 45.1 38.1 35.6 32.5
Year 30.0 21.6 12.7 5.5 -0.6 -6.2
For the north pole itself, Mohn gives the follow-
ing results, obtained by graphic methods:
MEAN TEMPERATURES OF THE NORTH POLE.
Jan. Feb. Mar. Apr. May June July
-41.8° -41.8° -31.0° -18.4° 8.6° 28.4° 30.2°
Aug. Sept. Oct. Nov. Dec. Year
26.6° 8.6° -11.2° -27.4° -36.4° -8.9*
160
CLIMATE
It appears that the region about the north pole is
the coldest place in the northern hemisphere for the
mean of the year, and that the interior ice desert of
Greenland, together with the inner polar area, are to-
gether the coldest parts of the northem hemisphere in
July. In January, however, Verkhoyansk, in north-
eastem Siberia, just within the Arctic circle, has a
mean temperature of about — 60°, while the inner
polar area and the northem interior of Greenland
have only —40°. Future exploration in the im-
mediate vicinity of the north pole may show
a lower January mean temperature there than at
present appears. Such exploration will, moreover,
certainly necessitate readjustment of the isothermal
lines as now drawn for this polar area. It may be
noted that the isotherm of 32° in January crosses the
Arctic circle in the north-eastem Atlantic. Else-
where it is south of this line. By December all land
within the Arctic circle is below the freezing point.
Thus far no minima as low as those of north-eastem
Siberia have been recorded in the Arctic, and the
Arctic maxima are much lower than those of Siberia.
During the last Peary expedition, the winter of
1905-06 was distinguished by “ comparatively high ”
temperatures.
For the Antarctic our knowledge is still very frag-
mentary, and relates chiefly to the summer months,
but the numerous well-equipped expeditions of the
last ten years have brought back very valuable re-
sults, extending in a few cases over all parts of the
CHARACTERISTICS OF ZONES—POLAR 161
year. On the February south polar isothermal chart
published in 1898 (after Buchan), the isotherm of
80° was shown essentially coincident with the Ant-
arctic circle, while a part of the isotherm of 25° was
drawn inside of the circle. Using the newest data
available, Hann has determined the mean tempera-
tures of the higher southem latitudes as follows:1
MEAN TEMPERATURES OF HIGH SOUTHERN LATITUDES.
S. Lat. 50° 60° 70° 80°
Mean Annual 41.9° 28.4° 11.3° -3.6°
January 46.9 37.8 30.6 20.3
July 37.2 18.3 —8.0 -24.7
These temperatures can be compared with those
given on page 159, for northern latitudes. From
lat. 70° S. polewards, Hann finds that the southem
hemisphere is colder than the northern. Antarctic
summers are decidedly cold. The mean temperature
of the warmest month over the whole Antarctic zone
is below the freezing point,2 while within the Arctic
circle mean temperatures above 82° are generally
found, except in the interior of Greenland and
around the pole. The low temperatures of the
south polar summer, which are probably due to the
great Continental mass of ice around the south pole,
are responsible for much of the difficulty and disa-
1 Nature, Jan. 5, 1905, p. 221.
2 At Cape Adare, a mean January temperature of slightly over
32° was obtained on one expedition, under abnormally favourable
conditions.
SS
162
CLIMATE
greeable character of Antarctic exploration. They
prevent much melting of snow and ice, and are
monotonous and depressing. The mean annual tem-
peratures experienced have been in the vicinity of
10°-15°, and the minima of an ordinary Antarctic
winter go down to —40° and below, but so far no
minima of the severest Siberian intensity have been
noted. The British expedition on the Discovery re-
corded — 67.7° at Cape Armitage at noon, May 16,
1903, and also noted — 40° in midsummer. The
maxima have varied between about 85° and 50°.
The temperatures at the south pole itself fumish
an interesting subject for speculation. It is likely
that near the south pole will prove to be the coldest
point on the earth’s surface for the year, as the dis-
tribution of insolation would imply, and as the
conditions of land and ice and snow there would
suggest. There is, however, room for doubt whether
the lowest mean annual temperature will be at the
mathematical pole. It is almost certain that the low-
est winter and summer temperatures in the southem
hemisphere will be found in the immediate vicinity of
the pole. One attempt to draw isotherms for the
Antarctic zone, on the basis of the recent data, is that
of Passerat, who has charted the mean winter and
mean summer temperatures. Obviously these charts
are based on extremely incomplete data, and can only
be regarded at best as tentative in the highest degree.
On the mean winter chart, the isotherm of —4°
(—20° C.) is mostly within the Antarctic circle, and
CHABACTERISTICS OF ZONES—POLAR 163
in places well within it, while —13° (—25° C.) ap-
pears between lats. 70° and 80° on Graham Land
and Victoria Land. On the mean summer chart the
isotherm of 82° (0° C.) is about half within and half
without the Antarctic circle, and partly within lat.
70°. The isotherm of 23° (—5° C.) appears on
Victoria Land, between lats. 70° and 80°. Krebs
has attempted to draw isotherms for the far Southern
latitudes, using the data collected during the years
1901-1904. The isotherms on the mean annual
isothermal chart of the world given in Hann’s
Lehrbuch der Meteorologie have been extended to
include latitudes up to 80° S. The lowest tempera-
ture shown is indicated by portions of the isotherm of
— 4° at about latitude 80° S.
It must not be supposed that the isotherms in the
Antarctic region run parallel with the latitude lines.
They bend polewards and equatorwards at different
meridians, although much less than in the Arctic.
The annual march of temperature in the north polar
zone, for which we have the best comparable data, is
peculiar in having a much-retarded minimum, in
February or even in March—the result of the long,
cold winter. The temperature rises rapidly towards
summer, and reaches a maximum in July. Autumn
is warmer than spring. Winter comes on gradually,
the summer slowly “ falling asleep.” The polar type
of annual march of temperature is illustrated in the
accompanying curves (See Fig. 33.).
The continents do not penetrate far enough into
Fig. 33. Annual March of
Temperature : Polar Type
N. Z., Novaya Zemlya. F. J.t
Franz Joseph's Land. G. L.
Grinnell Land.
164
-
CHABACTERISTICS OF ZONES—POLAR 165
the Arctic zone to develop a pure Continental climate
in the highest latitudes. Verkhoyansk, in lat. 67° 6'
N., almost on the Arctic circle, furnishes an excellent
example of an exaggerated Continental type for the
margin of the zone, with an annual range of 120°.
One-third as large a range is found on Novaya
Zemlya, The diurnal period of temperature is noted
during the time when the sun is visible, but is hardly,
or not at all, perceptible during the dark season.
During the latter, according to the Frarn observa-
tions, the day hours are usually colder than the night
hours. This appears to be an effect of winds, for
colder, northerly winds prevailed during the hours of
daytime, and milder, southerly winds by night. Polar
climate as a whole has large annual and small
diurnal ranges, but sudden changes of wind may
cause marked irregular temperature changes within
twenty-four hours, especially in winter. The small
ranges are associated with greater cloudiness, and
vice versa. The mean diurnal variability is very
small in summer, and reaches its maximum in win-
ter, about 7° in February, according to Mohn.
Pressure and Winds. Owing to the more sym-
metrical distribution of land and water in the South-
ern than in the northern polar area, the pressures and
winds have a simpler arrangement in the former, and
may be first considered. Recent Antarctic explora-
tion has considerably modified some of the views
which have been held regarding the general winds of
the south polar area, and their controlling pressures.
166
CLIMATE
The rapid southward decrease of pressure, which is
so marked a feature of the higher latitudes of the
southem hemisphere on the isobaric charts of the
world, does not continue all the way to the south pole.
Nor do the prevailing westerly winds, constituting
the “ circumpolar whirl,” which are so well developed
over the southem portions of the Southern hemi-
sphere oceans, blow all the way home to the south
pole. The steep poleward pressure gradients of these
southem oceans end in a trough of low pressure,
girdling the earth at about the Antarctic circle.
From here the pressure increases again towards the
south pole, where a permanent inner polar anticy-
clonic area is found, with outflowing winds deflected
by the earth’s rotation into easterly and south-easterly
directions. A chart of the south polar isobars for
February (after Sir John Murray and Dr. Buchan),
published in 1898, showed a pressure of 29.00 inches
in the low pressure girdle, and the isobar of 29.50
inches around the inner polar area. These easterly
winds have been observed by the recent expeditions
which have penetrated far enough south to cross the
low pressure trough. The limits between the pre-
vailing westerlies and the Outflowing winds from the
pole (“ easterlies ”) vary with the longitude and mi-
grate with the seasons. The change in passing from
one wind system to the other is easily observed. The
Belgica, for example, in lats. 69^°-711/2° S., and
longs. 81°-95° W., was carried towards the west by
the easterly winds in summer, and in winter was
CHARACTERISTICS OF ZONES—POLAR 167
driven east by the westerlies, and then again to the
west. The Belgica thus lay in winter on the equa-
torial, and in summer on the polar side of the trough
of low pressure. The seasonal change in wind direc-
tion was very marked, being almost monsoon-like in
character. On the other hand, the English expedi-
tion at lat. 77° 50' S. was persistently on the polar
side of the trough, with dominant S., S.E., and E.
winds. The smoke from Mt. Erebus, however,
showed prevailing south-westerly currents. The
German expedition on the Gauss was also under the
régime of the easterly winds during its stay in winter
quarters. The Belgica had fewer calms than some
stations nearer the pole. The south polar anticy-
clone, with its surrounding low pressure girdle, mi-
grates with the season, the centre apparently shifting
polewards in summer and towards the eastern hemi-
sphere in winter. The cloudier winds are poleward;
the clearer winds blow out from the pole. The out-
flowing winds from the polar anticyclone sweep down
across the inland ice and are usually cold. Under
certain topographic conditions, descending across
mountain ranges, as in the case of the Admiralty
Range in Victoria Land, these winds may develop
high velocity and take on typical foehn character-
istics, raising the temperature to an unusually high
degree. From the fact that certain warm, southerly
winds have been reported from the mountainous
eastern coast of Victoria Land as being damp and
snow-laden, Sir Clements Markham has suggested
168
CLIMATE
that they come from an open ocean, beyond the south
pole. Foehn winds have been noted in the South
Orkneys, from W.N.W. They are also known on
both coasts of Greenland, when a passing cyclonic
depression draws the air down from the icy interior.
These Greenland foehn winds are important climatic
elements, for they blow down warm and dry, raising
the temperature even 80° or 40° above the winter
mean, and melting the snow.
In the Arctic area the wind systems are less clearly
defined, and the pressure distribution is much less
regular, on account of the irregular distribution of
land and water. The isobaric charts published in the
report of the Nansen Expedition show that the North
Atlantic low pressure area is more or less well de-
veloped in all months. Except in June, when it lies
over southem Greenland, this tongue-shaped trough
of low pressure lies in Davis Strait, to the south-west
or west of Iceland, and over the Norwegian Sea. In
winter it greatly extends its limits farther east into
the inner Arctic Ocean, to the north of Russia and
Siberia. Between May and August it is much less
well developed. The Pacific minimum of pressure is
found south of Bering Strait and in Alaska. Be-
tween these two regions of lower pressure, the divide
extends from North America to eastern Siberia. This
divide has been called by Supan the “ Arktüche
Windschdde." High pressures are found in North
America and in Siberia from September to March,
the maxima being in Asia. The belt of somewhat
CHABACTERISTICS OF ZONES—POLAR 169
lower pressure connecting these two maxima is situ-
ated between Bering Strait and the north pole. In
July and August the maximum pressure is between
Greenland and somewhat east of Spitzbergen. The
pressure gradients are steepest in winter. At the
pole itself, pressure seems to be highest (about 30.079
ins.) in April, and lowest (29.882 ins.^ from June to
September. The annual range is therefore only
about 0.20 in.
The prevailing westerlies, which in the high south-
em latitudes are so symmetrically developed, are in-
terfered with' to such an extent by the varying
pressure Controls over the northem continents and
oceans, in summer and winter, that they are often
hardly recognisable cn the wind maps. The isobaric
and wind charts prepared by Buchan show that on
the whole the winds blow out from the inner polar
basin, especially in winter and spring. During his
last expedition, in the winter of 1905-06, Peary
reports “every few days we had violent winds from
the south—sometimes in the shape of squalls of a few
hours’ duration, sometimes continuing as furious
gales for two or three days.” During a westerly
gale of six days’ duration (lat. 85° 12' N.) Peary and
members of his party drifted some seventy miles to
the eastward on the ice. .
In the European and North American polar areas
the annual march of pressure gives a spring maxi- •
mum, in April and May, and a minimum in January
or February. The daily fluctuations in pressure in
170
CLIMATE
these circumpolar latitudes are about twice as large
in winter as in summer.
Rain and Snow. Rainfall on the whole decreases
steadily from equator to poles. The amount of pre-
cipitation must of necessity be comparatively slight
in the polar zones (15-10 ins., and less), chiefly be-
cause of the small capacity of the air for water va-
pour at the low temperatures there prevailing; partly
also because of the decrease, or absence, of local con-
vectional storms and thunder-showers.1 Even cy-
clonic storms cannot yield much precipitation. The
polar zones, therefore, have a permanent defidency
of precipitation. Their deserts of snow and ice are
climatic deserts in more senses than one. These ex-
tended snow and ice fields naturally tend to give an
exaggerated idea of the actual amount of precipita-
tion. It must be remembered, however, that evap-
oration is slow at low temperatures, and melting is
not excessive. Hence the polar store of fallen snow
is well preserved; interior snow fields, ice sheets, and
glaciers are produced. Nansen is of the opinion that
the amount of condensed vapour, much of it being in
the form of “ frozen fog ” (hoar frost) and not readily
measurable, exceeds evaporation in the polar districts.
The commonest form of precipitation is naturally
snow, the summer limit of which, in the northem
hemisphere, is near the Arctic circle, with the excep-
tion of Norway. In lat. 70° N., at Boothia Felix,
1 Locally, under exceptional conditions, as in the case of the
western coast of Norway, the rainfall is a good deal heavier.
CHARACTERISTICS OF ZONES—POLAR 171
40 per cent. of the precipitation from June to August
comes in the form of snow. So far as exploration has
yet gone into the highest latitudes, rain falls in sum-
mer, and it is doubtful whether there are places near
sea-level where all the precipitation falls as snow.
It is also uncertain whether any mountains reach a
height where nothing but snow falls. Von Drygalski
believes that the inland ice-cap of Greenland, over
2600 feet above sea-level, meets these conditions.
Perhaps the interior of the south polar continent
never has rain. The snow of the polar regions
is characteristically fine and dry. Schwatka has
pointed out that the snow huts of the Eskimos could
not be built with the kind of snow that falls in the
United States. At low polar temperatures flakes
of snow are not found, but precipitation is in the form
of ice spicules. The £nest glittering ice needles
(“diamond dust”) often fill the air, even on clear
days and in calm weather, and, gradually descending
to the surface, slowly add to the depth of snow on the
ground. Dry snow is also blown up from the snow-
fields on windy days, interfering with the transpar-
ency of the air. Snowfalls at temperatures of — 40°,
and even below, have been reported from eastern
Siberian and Arctic stations. It is probable that
under these conditions the air is watmer aloft.
Humidity, Cloudiness, and Fog. The absolute
humidity must be low in polar latitudes, especially in
winter, on account of the low temperatures. Rela-
tive humidity varies greatly, and very low readings
172
CLIMATE
have often been recorded. Cloudiness seems to de-
crease somewhat towards the inner polar areas, after
passing the belt of high cloudiness in the higher lati-
tudes of the temperate zones (see table, p. 116). In
the marine climates of high latitudes, the summer,
which is the calmest season, has the maximum cloudi-
ness; the winter, with more active wind movement, is
clearer. The data and curve given below illustrate
these conditions (see Fig. 34). The summer maxi-
mum is largely due to fogs, which are produced where
warm, damp air is chilled by coming in contact with
ice. They are formed over open waters, as among
the Faroe Islands, for example, and open water
spaces, in the midst of an ice-covered sea, are com-
monly detected at a distance by means of the “ steam
fog” which rises from them. Fogs are uncommon
in winter, when they occur as radiation fogs, of no
great thickness. The small winter cloudiness, which
is reported also from the Antarctic zone, corresponds
with the low absolute humidity and small precipita-
tion. The coasts and islands bathed by the warm
ANNUAL MARCH OF CLOUDINESS IN POLAR LATITUDE8. MARINE
type. (Beven stations. Lat. 70° N.)
Jan. Feb. Mar. Apr. May June July Aug. Sept. Oct. Nov. Dec. Year.
7.1 6.8 6.4 7.0 7.7 8.3 8.5 8.2 8.0 8.0 6.8 6.6 7.5
waters of the Gulf Stream drift usually have a higher
cloudiness in winter than in summer. The place of
fog is in winter taken by the fine snow crystals, which
often darken the air like fog when strong winds raise
the dry snow from the surfaces on which it is lying.
CHARACTERISTICS OF ZONES—POLAR 173
As yet there is little detailed information concern-
ing the cloud forms and movements in the polar
zones, and the reports are rather confusing. The rec-
ords of the Nansen Expedition show a greater cloudi-
10
9
8
7
6
5
4
3
2
I
0
Fig. 34. Annual March of Cloudiness in the North Polar
Zone: Marine Type
ness by day, and with stronger winds. Cumulus forms
are rare, even in summer, and it is doubtful whether
this cloud occurs at all in its most typical develop-
ment. Clearly defined cloud forms have been re-
ported by some observers to be very rare indeed in
the Arctic, especially in the winter sky. On the other
hand, Lieutenant Royds, of the Discovery, reports
that he never saw such striking and beautiful ex-
amples of every kind of cloud as within the Antarctic
circle. At Griffith Island, in the north polar zone,
two months passed without clouds. And “ day after
day, with glorious clear skies and continuous sun-
shine ” is reported by the Discovery in the Antarctic.
174
CLIMATE
Stratus is probably the commonest cloud of high lati-
tudes, often covering the sky for days without a
break. In place of well-developed cloud forms, the
air is filled with fog in summer, which often grows
into poorly defined stratus clouds. Cirrus cloud
forms probably decrease polewards. At the South
Orkneys, cirrus was observed at altitudes of 6000
to 8000 feet. Nansen’s results give an average cloud
movement from W.N.W. and N.W. In the Ant-
arctic, Nordenskjöld reports cirrus from W. to
W.S.W., and the Belgica expedition noted cirrus
from the east in summer only.
Cyclones and Weather. • The prevailing westerlies
continue up into the margins of the polar zones.
Many of their cyclonic storms—the weather Controls
of temperate latitudes—also continue on to the polar
zones, giving sudden and irregular pressure and
weather changes. The inner polar areas seem to be
beyond the reach of frequent and violent cyclonic dis-
turbance. Calms are more common; the weather is
quieter and fairer; precipitation is less. Most of the
observations thus far obtained from the Antarctic
come from this marginal zone of great cyclonic ac-
tivity, violent winds, and wet, disagreeahle, inhospit-
able weather, and therefore do not show the features
of the actual south polar climate.
The most thorough study of cyclonic movements in
the highest latitudes is that in connection with the
Nansen expedition in the F ram. During the three
vears of her drift, depressions passed on all sides of
CHARACTERISTICS OF ZONES—POLAR 175
her, with a preponderance on the west. The direc-
tion of progression averaged nearly due east, and
the hourly velocity twenty-seven to thirty-four miles,
which is ahout that in the United States. The rainy
winds were usually S. and S.E., while N.E. and N.W.
were least likely to bring rain or snow. For the
higher latitudes, most of the cyclones must pass hy
on the equatorial side of the observer, giving “ back-
ing ” winds in the northem hemisphere. The main
cyclonic tracks are such that the wind characteristi-
cally backs in Iceland, and still more so in Jan Mayen
and on the eastern coast of Greenland, these districts
lying on the north and west of the path of progres-
sion. Frightful winter storms occasionally occur
along the east coast of Greenland and off Spitzber-
gen. During the drift of the Fram the southerly
winds were the warmest in winter and the northerly
the coldest, showing that, at the 82d parallel of lati-
tude, the Siberian cold pole ceases to have much
influence.
For much of the year in the polar zones the diurnal
control is weak or absent. The successive spells of
stormy or of fine weather are wholly cyclonically
controlled. Extraordinary records of storm and
gale have been brought back from the far south and
the far north. The Swedish Antarctic expedition,
for example, under Nordenskjöld, in 1902-08, ex-
perienced for five months, beginning in May, a period
of storms with short intermissions never exceeding
three days, and during all of this period the average
176
CLIMATE
wind velocity was twenty-three miles an hour, and
for a fortnight it averaged forty-five miles. The Dis-
covery reported a gale on July 19,1902, which lasted
ten hours with a velocity of eighty-five miles an hour.
Wind direction and temperature vary in relation to
the position of the cyclone. During the long, dreary
winter night the temperature falls to very low read-
ings. Snowstorms and gales alternate at irregular
short intervals with calmer spells of more extreme
cold and clear sides. The periods of greatest cold
in winter are calm. A wind from any direction will
bring a rise in temperature. This probably results
from the fact that the cold is the result of local radia-
tion, and a wind interferes with these conditions by
importing higher temperatures, or by mixing upper
and lower strata. During a northern polar winter
the average thickness of ice formed over the oceans,
where no storms or strong tides interfere, reaches six
feet and more. Nansen found a thickness of over
eight feet in one year. During the long summer
days the temperature rises well above the winter
mean, and under- favourable conditions certain
phenomena, such as the diurnal variation in wind ve-
locity, for example, give evidence of the diurnal con-
trol. But the irregular cyclonic weather changes
continue, in a modified form. There is no really
warm season. Snow still falls frequently. The
summer is essentially only a modified winter, from
the point of view of temperate zone man, especially
in the Antarctic, where accounts of low temperatures,
CHARACTERISTICS OF ZONES—POLAR 177
high winds, frequent fogs, and much cloud do not
give a very cheerful picture of weather conditions. In
summer, clear spells are relatively warm, and winds
bring lower temperatures. In spite of its lack of
high temperatures, the northem polar summer, near
the margins of the zone, has many attractive qualities
in its clean, pure, crisp, dry air, free from dust and
impurities; its strong insolation; its slight precipita-
tion. In certain places, as on the interior f jords of
Greenland and on the tundras of Asia and North
America, the summer brings swarms of gnats and
flies, which are an extreme annoyance, and the pre-
valent summer fogs are a serious disadvantage.
Twilight and Optica! Phenomena. The monotony
and darkness of the polar night are decreased a good
deal by the long twilight, due to the high degree of
refraction at low temperatures. The sun actually
appears and disappears some days before and after
the times which are geometrically set. Light from
moon and stars, and from the aurora, also relieves the
darkness. Optical phenomena of great variety,
beauty, and complexity are common. Solar and
lunar haloes and coronas, and mock suns and moons
are often seen. Auroras seem to be less common and
less brilliant in the Antarctic than in the Arctic.
Sunset and sunrise colours within the polar zones are
described as being extraordinarily brilliant and
impressive.
-
CHAPTER VII
THE HYQIENE OF THE ZONES
Introduction: Some General Relations of Climate and Health—
A Complex Subject—Climate, Micro-organisms and Disease—
Geographical Distribution of Disease—Tropics: General Physi-
ological Effects—Tropical Death-rates—Hygiene in the
Tropics—Tropical Diseases—Malaria—Yellow Fever—Dys-
entery—Diarrhoeal Disorders—Tropical Abscess of the Liver
—Cholera—Plague—Sunstroke and Related Conditions—
Dengue—Beri-beri—Other Minor Diseases—General Con-
clusions: Tropics—Temperate Zones: General—Winter and
Summer Diseases—Tuberculosis—Pneumonia—Diphtheria—
Influenza—Bronchitis—Rheumatism—Measles and Scarlet
Fever—Typhoid Fever—Whooping Cough—Cholera Infantum
—Hay Fever—Polar Zones: General—Scurvy—Climate and
Health: General Conclusions.
'Introduction: Some General Relation» of Climate
and Health. From earliest times people have sought
in atmospheric conditions an explanation of the oc-
currence of disease, and have often found in statistics
of mortality and of weather a more or less striking
parallelism. Many fairly ohvious facts naturally
point to some relation of cause and effect in this
matter. Some diseases are found principally in
the warmer climates; others seem to prefer the colder.
178
THE HYGIENE OF THE ZONES
179
Some are usually more active in the warmer, or the
drier, months; others have shown the contrary rela-
tion. High altitudes are free from some diseases
which prevail near sea-level, and have certain favour-
able climatic characteristics long recognised in the
treatment of disease. The pure air, increased res-
piration, and deeper breathing are stimulating and
health-giving; they are beneficial in many affections
of the lungs, although occasionally over-stimulating
in nervous and cardiac troubles. In the case of other
diseases, again, altitude has no effect. Dry climates,
especially deserts, whose air is usually exceptionally
pure and aseptic, are generally healthful, and are
beneficial in many cases where mountain climates are
too stimulating. The climates within forested areas
have proved especially favourable in cases of phthisis.
Ocean air, pure and dust-free, with its saline con-
stituents and equability of temperature, is beneficial
to most persons as a moderate tonic and as a restora-
tive in many illnesses. Winds are important agents
in promoting health. The cool, refreshing sea-breeze
of the tropics brings in pure air from the sea, and is
one of the most important desiderata in hot climates.
Winds are active ventilating and purifying agents
where population is congested. Fogs and clouds, by
cutting off sunlight, weaken one of the best agents in
promoting health, for the germicidal action of sun-
light has been proved by many investigators. Stern-
berg has called it “ one of the most potent and one
of the cheapest agents for the destruction of patho-
180
CLIMATE
genie bacteria,” and says “ its use for this purpose is
to be recommended in making practical hygienic
recommendations.” In London, a higher death-rate
after a long fog may, however, result from the lower
temperature during the fog, and not from any direct
effect of the fog itself.
A Complex Subject. Facts like the foregoing
naturally prejudice one in favour of a causal connec-
tion between atmospheric conditions and disease.
Nevertheless, such studies have often led to very con-
tradictory conclusions. Diseases usually character-
istic of one zone are known to spread widely over
other zones. Diseases which usually prefer the
warmer months sometimes occur in the coldest.
Rules, previously determined as the result of careful
investigation, often break down in a most perplex-
ing way. Some of the difficulty in this lack of agree-
ment results from untrustworthy statistica, often
collected under very varying conditions and really
not comparable. Curves are smoothed to such an ex-
tent that they can be made to show anything. Conclu-
sions are drawn in individual cases which are neither
of general application, nor do they even apply locally
on any other occasion than the special one in question.
Most of this disagreement comes from the fact
that not only may the different weather elements
themselves, temperature, moisture, wind, sunshine,
and so on, each have some effect in the produc-
tion of a disease, which it is impossible to determine,
but so many other factors are concemed in the mat-
THE HYGIENE OF THE ZONEB
181
ter that confusion and contradiction in the conclusions
reached are inevitable. Sanitation, food, water, habits,
altitude, character and moisture of the soil, race,
traffic, and other Controls serve to complicate the
problem still further. In most studies of climate
and health some, or even many, of these factors have
not received attention. Hence the results have
usually been incomplete. Local, peculiar, and tem-
porary conditions may play a large part in the pre-
valence of disease. Overcrowding under unhygienic
conditions, especially indoors during cold weather,
and traffic by rail, steam, caravan, or on foot, are often
more important than climate. The frequent escape
of mountain, of desert, and of polar peoples from epi-
demics is to be attributed in most cases to the smaller
chance of importing disease because of little inter-
course with the outside world, and of spreading it,
when imported, because of the scattered population.
It may be noted, however, that the crowding indoors
and the sparseness of population in these two cases
are more or less directly climatically controlled.
Climate, Micro-organisms and Disease. The
cause of disease Ls now no longer sought directly
in meteorological conditions, but in the effects, more
or less direct, of these conditions upon the micro-
organisms which are the specific cause of the disease.
Atmospheric conditions may help or may retard the
development of the micro-organism, and may
strengthen or weaken the individual’s power of
resistance against the attacks of the germ, as well as
182
CLIMATE
affect his susceptibility. Thus new views have re-
placed the old. Winds used to be regarded as the
chief agents in spreading epidemics: now it is known
that disease cannot be carried far by winds, for the
micro-organisms do not long maintain their power in
the free air and under the sun. Rain has been sup-
posed directly to control the distribution of diseases:
now we believe that precipitation acts only indirectly,
through drinking water, or through its control of
the dust in the air. Dust from dry soil may
contain the geruis of infectious diseases, and aggra-
vates affections of the respiratory organs. Harm-
ful exhalations are no longer believed to be given off
by the soil, but the condition of the soil as to moisture
and temperature may affect the development and
diffusion of certain micro-organisms. Some parallel-
ism has been discovered between the prevalenoe of
certain diseases, such as diarrhoea and typhoid fever,
and soil temperatures or the ground-water level.
Geographical Distribution of Disease. The scheme
of classifying disease geographically, on a broad
climatic basis, is attractive, but not very satisfactory.
For, on the one hand, many diseases are practically
universal in extent, showing great independence of
climate, and on the other, the history of many dis-
eases is still in the making. In the distribution of
disease too many factors are concemed to make any
simple and accurate treatment possible as yet. In
spite of this complexity, however, certain broad gen-
eral statements may be made, useful in enabling the
THE HYGIENE OF THE ZONES
183
layman properly to co-ordinate his ideas on the sub-
ject, and fairly accurate within reasonable limits.
Tropics: General Physiological Effects. The uni-
formly high temperatures of the tropics, especially
when combined with high humidity and the character-
istically small diurnal variability of temperature,
have certain fairly well established physiological
effects. Among these the following are commonly
noted: increased respiration; decreased pulse action;
profuse perspiration; lessened activity of stomach
and intestines, and tendency to digestive disorders; a
depression of bodily and mental activity, enervation,
indifference, disinclination to exertion,—in fact, a
general, ill-defined condition of debility; increased
activity of the liver; surexcitation of the kidneys. In
damp, hot air, evaporation from lungs is slight; the
blood becomes more diluted; there is a deficiency in
the number of red corpuscles in consequence of the
diminished proportion of oxygen in the air. There
is less power to do work; greater fatigue from work;
lowered vitality. All this renders the body less able
to resist disease. An anaemic condition in the moist
tropics is widespread.
Tropical Death-rates. As compared with the
death-rates in colder latitudes, tropical death-rates
average high. They range from the appalling rate
of 483 per 1000 among European troops on the Gold
Coas{ in 1829-1886, through 121 per 1000 for
European troops in Jamaica in 1820-1886, down to
so low a rate as 14.84 per 1000 for British troops in
184
CLIMATE
India in 1896. These death-rates, however, repre-
sent such very diverse conditions of season, climate,
race, occupation, soil, mode of life, food, dwelling,
etc., that they cannot legitimately be compared with
one another. The prevalence of some special dis-
ease in exceptionally virulent or widespread develop-
ment will raise the death-rate of any year far
beyond its usual figure. Again, the presence of some
insect which causes loss of crops, and the resulting
lowered vitality of the people in consequence of in-
sufficiënt food, may easily swell the death-rate. Nor
can these tropical death-rates properly be compared
with the death-rates noted under different conditions
in other latitudes. (A recent attempt to compare the
death-rate among American troops in the Philippines
with the general death-rate in certain American cities
is an excellent example of the danger of comparing
two totally different things). So various and so
complex are the controlling factors that critical com-
parative study is not worth while. Tropical death-
rates are certainly high, but this fact should not be
attributed solely to the dangers of the climate. Bad
sanitary conditions and lack of medical attendance
account for many, if not most, of the high tropical
death-rates among the natives; and an irrational mode
of life explains many deaths among persons coming
from cooler climates. Tropical death-rates are be-
ing reduced with remarkable rapidity in all coun-
tries which are wholly or partly under white control,
and especially among European troops in the
THE HYGIENE OF THE ZONES
185
tropics. This is the result of experience with tropical
conditions, and of the increased precautions which
are now taken in selecting and caring for the men.
Hygiene in the Tropics. Under the special condi-
tions of tropical climates, the resident who comes
from a cooler latitude needs to take special precau-
tions regarding his mode of life and personal hy-
giene. A rational, temperate mode of life, especially
the avoidance of alcoholic excess; regular exercise;
non-fat-producing food; clothing suited to the cli-
mate, such as duck or linen for outside garments dur-
ing the day, and light woollen for the cool of the
evening and night; careful attention to the site and
construction of dwellings; all possible sanitary pre-
cautions; keeping cool during the warmest hours and
season by the use of fans or punkahs, by frequent
baths, and by abstaining from hard work; protection
against mosquitoes by means of sereens; frequent
change of climate by retuming to cooler latitudes,—
all these are important. It seems like a contradic-
tion, but it is a fact, that the danger of taking cold
in the tropics is very great, and must be carefully
guarded against. General Wolseley is reported to
have said of the tropics, “ not to get cold is to avoid
almost certainly all the causes of disease,” and a re-
cent writer has well said that these words should be
inscribed on the walls of all barracks in the tropics.
The situation may be summed up in the rule: “ Re-
spect the sun, and rain, and wind; clothe with a view
to avoiding chili, and live temperately.” The dan-
186
CLIMATE
ger of becoming chilled is greatest during the cooler
hours of evening and night, during rains, or when
cool winds blow. The skin does not react well in the
tropics, hence chills are frequent with even slight tem-
perature changes, especially when there is wind. As
to the best style of dwelling for the tropics, there is
no absolute agreement. The material can best be
determined by the local conditions in each case.
Wood, stone, and thatch are employed successfully.
Of whatever construction, houses should be roomy
and airy, and protected against direct sunshine dur-
ing the hottest hours of the day.
Tropical Diseases. In addition to the physiologi-
cal effects just considered, certain diseases are so
much at home in the tropics that they have come to
be known as tropical diseases. This designation,
however, as Sir Patrick Manson uses it in the title of
his famous work, does not mean diseases confined
to the tropics, but is employed in a meteorological
sense for diseases associated with, but not solely or
even directly due to, high temperatures. Tropical
climatic conditions, per se, piobably do not injuri-
ously affect the natives of the tropics any more than
do the conditions of extra-tropical climates affect
those who live in them.
Sir Patrick Manson has made the fact very dear
that the difference between the diseases of tropical
and extra-tropical latitudes lies in the specific cause
of these diseases. For the development of certain
disease germs, certain temperatures are required.
THE HYGIENE OF THE ZONES
187
Sometimes the temperature is too high; sometimes
too low. Again, certain media are necessary in
propagating certain diseases, as e. g., a third organ-
ism, other than the disease germ itself, and man, who
has the disease. The third organism may be a tropi-
cal species, as in the case of the tsetse fly; if so, the
disease is a tropical disease. The opportunity for
contracting the disease is best, or exists solely, in the
tropics. Again, some diseases are the result of
toxins generated by germs living in an external med-
ium. One condition of development of these germs
may be a certain high temperature. Thus the dis-
ease is a tropical disease, e.g., beri-beri. On the
other hand, when everything seems favourable, nat-
ural enemies of the germs themselves, or of the
organism which subtends the germs, may destroy
them. Dr. Manson’s conclusion, which is the result
of careful study, may well be accepted as an authori-
tative statement. “ The more we learn about these
diseases, the less important in its hearing on their
geographic distribution, and as a direct pathogenic
agency, becomes the róle of temperature per se, and
the more the influence of the tropical fauna.”
Besides the more or less direct effects of exposure
to tropical sun and heat, such as sunstroke, heat ex-
haustion, and the like, there are malaria, in varied
forms, and dysentery, the two worst enemies of white
residents in the tropics; dengue; ulcers; yaws; tropi-
cal ahscess of the liver, a common and dreaded dis-
ease; diseases like yellow fever, cholera, and plague,
V
188
CLIMATE
which are more or less limited to certain localities, and
are being hemmed in more and more by modern sani-
tary measures; many other infectious diseases which
are common to colder as well as warmer latitudes; and
beri-beri, elephantiasis, and other diseases which at-
tack the coloured race chiefly, and are therefore of a
medical rather than of a practical interest to white
people. The fact that plague, and leprosy, and to
some extent cholera as well, are practically limited
to the tropics, is the result of modern sanitary precau-
tions in the extra-tropics. The unsanitary condi-
tions among tropical peoples favour the spread of
these and similar diseases, and not the climate per
se. Nevertheless it is as clear as day, in the words of
Dr. Manson, that these very unsanitary conditions
are “ more or less an indirect outcome of tropical cli-
mate.” There is a greater variety in tropical than
in extra-tropical diseases, but then many diseases
common in cooler latitudes prevail also near the
equator, and many diseases prevail near the equator
which have practically been banished from higher
latitudes. Tropical climate is not the sole, or even
in many cases the determining factor. Most
tropical diseases attack both natives and whites;
sometimes the former suffer most; sometimes the
latter. There is no rigid rule; but the racial element
is often very potent.
Malaria. Malaria, next to tuberculosis one of the
most important of diseases, was formerly considered
a poisonous, gaseous emanation from the soil. It is
THE HYGIENE OF THE ZONES
189
now known to be a germ disease. In 1880, Laveran,
a French army surgeon in Algiers, discovered a para-
site in the blood of malarious persons. Manson later
suspected mosquitoes as thê means of propagating
the malarial parasite. (Dr. A. F. A. King, of
Washington, ,D. C., had advanced a similar sugges-
tion in 1841.) Ross, at Manson’s suggestion in
1894, followed up the clue in India, and established
the fact. His work, and that of Grassi, Koch, and
others, has shown that the insect here concemed is a
mosquito of the single genus Anopheles, and that
malaria is due mainly, if not solely, to the injection
of the parasites into the blood of human beings by
the bite of mosquitoes previously infected by stinging
some human heing suffering from malaria.
Malaria is very widely distributed, from the polar
circles to the equator, but the endemic foei, Manson
points out, tend to become more numerous towards
the equator. There is, on the whole, a fairly regular
decrease in frequency and in severity from equator
poleward. In certain parts of the tropics, as, for ex-
ample, the Gold Coast, the mouths of the Congo and
Zamhesi, New Guinea, etc., malaria is so prevalent
and so severe that the question of residence there for
the white race has been practically controlled thereby.
The disease is commonly associated with swamps,
and moist low-lying districts, while uplands and
well-drained areas are usually less afïected. This
relation, however, seems to be somewhat less appar-
ent in the tropics than in higher latitudes. Malaria
190
-
CLIMATE
is perennial in the tropics, with a general tendency to
a maximum in the wanner or rainy season. In the
temperate zone the maximum is in late summer or
early autumn.
It is clear, with the mosquito theory so well estab-
lished that Koch can say, of tropical Africa, “ where
there are mosquitoes there is malaria, and where there
are no mosquitoes there is no malaria,” that the older
views regarding the relation of climate and soil to
malaria must have undergone some change. Never-
theless, there is still a fairly definite relation of cause
and effect in this matter. For the development of
the malarial parasite in the body of the mosquito a
certain degree of heat is necessary, probably a mean
temperature of at least 60° F. Hirsch pointed out,
some years ago, that 60° F. is the limit at which ma-
larial fevers can occur. Hence it happend that the
same mosquito may be harmless at low temperatures
and dangerous at higher. Rainfall is important be-
cause the malaria-bearing mosquito passes part of its
life in water. Hence lakes, and especially marshes,
pools, and swamps are critical Controls as breeding-
places of the mosquitoes. Rain thus differs in its
effects according to the amount of precipitation, and
according to the conditions present where the rain
falls. A rain which in one place floods and scours
out mosquito-breeding pools, in another may just
suffice to fill hollows and low-lying places where
mosquitoes may then breed. Digging up the soil,
whether for the first time or not, may result in hol-
THE HYGIENE OF THE ZONES
191
lows where puddles and pools may collect, and thus
give rise to malaria. The ground-water level, by
afïecting soil-moisture, also plays a part, but decom-
posing vegetable matter is no longer believed to be
an essential. Many occurrences or non-occurrences
of malaria, unexplained on any meteorological
grounds, may be ascribed to the presencé or absence
of the malaria-bearing mosquito.
The best prevention of malaria is to screen persons
who have the disease, so that they cannot infect mos-
quitoes, and to screen all doors and Windows so that
healthy individuals may not be bitten by infected
mosquitoes. Wholesale protection of this kind has
recently been attempted in Havana, on the Isthmus
of Panama, in West Africa, and elsewhere. The
danger of being bitten by the Anopheles, whose habits
are chiefly nocturnal, is greatest at night, but resid-
ence in tropical malarial districts for white persons
is always safest away from native huts and villages.
The draining and filling up of swamps, pools, and
puddles; levelling of the surface of the ground; culti-
vation of the soil by planting trees or other forms of
vegetation; destruction of the larvae by pouring oil
on the standing waters; location of dwellings on
high, dry sites; having these dwellings properly
screened,—all these precautions should be taken.
Further, a rational and scientific use of quinine, and
a change of climate to a higher latitude, are both very
important measures in case of the contraction of the
disease. Residence at an altitude of a few thousand
192
CLIMATE
feet, where the temperature is lower than at sea-
level, is usually a sure preventive, but the mountain
climates may be injurious to persons suffering from
heart or lung troubles, or from rheumatism.
Relapses are very common after a malarial attack,
and an ansmic condition may continue for a long
time. According to Koch, these relapsing cases in-
fect the new mosquitoes each spring, but the same
authority believes it possible to destroy all the para-
sites in such cases, before the spring comes, by the
use of quinine.
Malaria is one of the greatest obstacles in the way
of white occupation of many tropical countries.
Ross spoke well when he said that the success of im-
perialism depends largely on success with the micro-
scope. The hope for the future lies in the determined
effort to destroy the malaria-bearing mosquitoes, and
to protect individuals from infection by these mos-
quitoes. Preventable, to a large extent, malaria cer-
tainly is, but it is beyond the range of human power
to eradicate the disease, certainly within any time
which is of present political interest. In the light
of the new discoveries, however, white residents in
the tropics are now in far less danger from malarial
infection than they were a few years ago.
TelUm Fever. Yellow fever is endemic only on
the eastern coast of the Americas, and on the western
coast of Africa, chiefly within the tropics, although it
frequently extends beyond them, as an epidemie, even
to latitudes between 40° and 50°. It frequents
THE HYGIENE OF THE ZONES
193
especially the squalid quarters of seacoast towns and
the shores of large navigable rivers, readily follow-
ing railways, canals, and other highways of travel.
The opening of the Panama Canal and the establish-
ment of new steamship lines between Central Amer-
ica and the Hawaiian and Samoan Islands, where
no yellow fever has occurred, may easily be fol-
lowed by the introduction of the disease into those
islands. Within the tropics the rainy season brings
the maximum prevalence of the disease; in extra-
tropical latitudes, the summer and autumn. Hirsch
asserts that it has not gained a foothold at tempera-
tures below 68° F. Manson states that a tempera-
ture over 75° F. is needed for its development in
epidemie form. Yellow fever weakens as cold
weather approaches, and epidemics disappear when
the temperature reaches 32° F., although the vitality
of the germ may not be extinguished by frost
(Manson). Stations more than a few hundred, or
thousand, feet above sea-level are free from the dis-
ease, probably because of their lower temperatures.
The altitude of this zone varies, but at the maximum,
yellow fever has only very rarely occurred as high as
4000 feet above sea-level.
The actual cause of yellow fever is still unknown.
The brilliant work of Reed, Carroll, Agramonte, and
Guiteras has shown that the intermediate host, and
the diffusing agent of the yellow fever parasite is a
mosquito of the genus Stegomyia fasdata, which has
previously been infected by biting a person suffering
194
CLIMATE
from yellow fever. The disease is non-contagious
where S. fasdata is not present, as at Petropolis,
near Rio de Janeiro. Vigorous campaigns against
the mosquito have recently produced a remarkable
decrease of the disease at Havana, on the Isthmus of
Panama, and at New Orleans in 1905. The endemic
character of yellow fever in Rio is believed by
Manson to be kept up by the continual arrival of
foreigners who are susceptible to the disease. New-
comers are chiefly attacked. After one attack, im-
munity is usually secured. Persons who have lived
for some time in endemic areas without having the
fever are more or less exempt, or may have the dis-
ease in mild form. The immunity of natives who
leave their home decreases with the length of their
absence. Negroes enjoy comparative immunity; the
yellow race is more, and the white race most, suscep-
tible. Of the white race, northerners are more sus-
ceptible than southerners.
Dysentery: Diarrhceal Disorders. Dysentery oc-
curs epidemically in all latitudes, but has its home in
the warmer climates, as a whole increasing in severity
and frequency with approach to the equator. Some
form of dysentery is almost always present in lower
latitudes, where this disease is next in importance to
malaria in causing high death-rates and in its lasting
effects. High temperatures are clearly necessary
for the development of the disease germ, but numer-
ous other Controls are also needed. The maximum
is usually in the hottest, or wettest, months; cooler
THE HYGIENE OF THE ZONES
195
weather checks the disease. In India, the latter half
of the rainy season shows the maximum. Altitude
cannot be relied on to give relief from dysentery;
residents on mountains often suffer more than those
at lower levels. Lack of sanitary precautions, im-
pure water, overcrowding, poor food, excesses of all
kinds, are predisposing causes. The best preventive
is a rational, temperate mode of life; protection of the
more susceptible parts of the body against chills, and
a proper regulation of the whole system. Epidem-
ics of dysentery seem independent of the effects of
wind, rain, and atmospheric humidity. Immunity
is not secured after one attack, several attacks being
common.
In extra-tropical latitudes, diarrhoeal disorders
show a similar dependence on temperature, for they
are most frequent in summer and early autumn.
Usually the hotter the summer, the greater the pre-
valence and the severity of these complaints, and the
higher the death-rate from them. Other factors are,
however, concemed in this matter, so that “all at-
tempts to express the diarrhoeal mortality of a given
place as a function of the temperature only have
failed.” Soil temperature is one factor between
which and the death-rate from diarrhoeal disorders
some relation has been made out.
i
Tropical Abscess of the IAver. Rare in temper-
ate and cool climates, tropical abscess of the liver, as
the name implies, is mainly a disease of warmer lati-
tudes and usually accompanies or follows dysentery.
196
CLIMATE
Among the predisposing causes the most potent are
injudicious and intemperate habits, especially over-
eating and over-indulgence in alcoholic beverages;
insufficiënt exercise; exposure; chills, and in general
the “ congestive and degenerative conditions inciden-
tal to tropical life.” Heat, malaria, and dysentery
are active precursors of liver abscess, in that they
lower the vitality. The disease is most common dur-
ing the colder or rainier season, when chills are most
frequent, but temperature is not the sole control.
The physiological adjustment of a person from a
colder latitude to tropical conditions of climate throws
a considerable strain upon the liver. The result,
especially if intemperate living is indulged in, is
likely to be liver abscess. Chiefly because of their
disregard of proper hygiene, white men and women
are generally more liable to have the disease than na-
tives; the death-rate among white troops in the tropics
is much higher than among native troops in the case
of this disease. Tropical liver abscess is most, but
by no means solely, to be expected in the earlier years
of residence in the tropics. Persons suffering from
the disease should, if possible, be sent to a temperate
climate, although there are many cases of recovery
even in the tropics.
Cholera. Cholera is due to the specific microbe,
the comma bacillus, discovered by Koch in 1883.
From its home in India, it has spread in great waves
as an epidemie over most of the globe, the last ad-
vance reaching its maximum extension early in the
THE HYGIENE OF THE ZONEB
197
decade 1890-1900, in northern Europe. Cholera
has gone as far north as Bergen in Norway, and in
Siberia up to about latitude 60° N. No general re-
lations can be established between the occurrence of
cholera and climatic or weather conditions. Local
conditions exercise an important control. In higher
latitudes, however, cholera seems most frequent to-
wards autumn, decreasing with falling temperatures.
Cholera is chiefly prevalent in low-lying places, on
river banks, and where human beings are over-
crowded under unsanitary conditions. The at-
mosphere is clearly not the agent for carrying the
bacillus, for the latter does not keep its morbific char-
acter long in the free air. The principal agent in
spreading the disease is traffic; but drinking-water
certainly also plays a part. As a whole, cholera is
rarer and milder in the higher latitudes, and has de-
creased in Europe in cold weather, coming up again
in summer. It has, however, also been active at low
temperatures. With many exceptions, there may be
said to be a decrease with altitude, and soil moisture
may also play a part.
Plague. The specific cause of plague is a bacillus
discovered by Kitasato, a pupil of Koch, in 1894, and
also independently by Yersin. Formerly very wide-
spread, plague is now confined to the sub-tropical dis-
tricts of Southern Asia and of the Mediterranean.
It has become a disease of warm climates, because
it depends upon the unsanitary conditions in which
tropical natives live, and it attacks the poorer part of
198
CLIMATE
the population. Filth, famine, social misery, anJ.
overcrowding are predisposing causes. The con-
clusions regarding the relation of plague to weather
and climate are almost as numerous as are those who
have investigated this subject, but it is clear that
plague is not limited by isotherms, and that meteoro-
logical conditions do not spread it, or solely control
it. The Indian Plague Commission concludes that
there is no direct connection between plague and
climate; Hirsch had previously stated that the rela-
tion is unsettled. In the tropics, however, the dis-
ease has, on the whole, had a cool season, and in
higher latitudes a warm season, maximum. As to
altitude, plague has occurred at high levels in cold,
dry climates, and at low levels where the climate is
warm and moist. It has prevailed when the tem-
peratures were so low that people suffered with the
cold (Roumelia, 1787-8), and at temperatures so
high that sunstrokes occurred (Smyrna, 1785).
On the whole, plague has chiefly prevailed under
moderately high temperature and moisture condi-
tions, and where the soil is damp and the ground low.
These facts do not, however, necessarily point to
cause and effect.
The best preventives of plague are pure air and
modern sanitation. In India, Haffkine has been
very successful with inoculation. Plague travels by
trade routes. Persons sick with, or incubating
plague, and infected clothing and personal effects,
carry the infection.
THE HYGIENE OF THE ZONES
•199
1Simstroke and Related Conditions. Several dis-
agreeable and some fatal results of heat and hu-
midity, not to be classed as diseases, are common in
the tropics, and to a considerable extent also in extra-
tropical latitudes, even as far as latitude 50° to 60°
N. Sunstroke and heat prostration are most com-
mon in the tropics when the air is damp during calms,
and in temperate latitudes during the hottest spells
of summer, when the weather conditions are tropical
in character. The germ origin of sunstroke has
been maintained by Sambon, but the cause is to be
found in the effects of insolation, direct and reflected;
the air temperatures, and the undue heating of the
body. The skin of white persons when exposed to
the sun in the tropics often becomes burned and
blistered, and travellers commonly suffer because of
lack of protection of neck or limbs under sunshine.
Exposure to the sun does not always explain sun-
stroke, for at sea the tropical sun is less fatal than on
land,1 and places with apparently similar conditions
of insolation differ much as regards the prevalence of
sunstroke. A great deal doubtless depends on oc-
cupation. Many forms of heat exhaustion are in-
duced by exposure to high temperatures, but greatly
aggravated by unsuitable clothing, impaired physical
condition, and intemperance.
A study of the sunstroke weather of August,
1896, in the United States, led Dr. W. F. R. Phillips
1 Stokers and firemen suffer from prostration on steamers in the
tropics, but here artificial heat is partly responsible.
200
CLIMATE
to conclude that the number of sunstrokes followed
the excess of the temperature above the normal more
closely than it did any other meteorological element;
that there was no definite relation to the relative or
absolute humidity; and that the liability to sunstroke
increased in proportion as the mean temperature of
any day approached the normal maximum tempera-
ture for that day.
Sunstroke is most common among those who are
exposed to the sun, and at hard work under condi-
tions which retard or check the cooling of the body
by radiation or conduction. The best protection
against simstroke and heat prostration in general,
and especially in the tropics, is to be found in the use
of suitable light and loose clothing; loose, wide-
brimmed, and well-ventilated headgear; avoidance of
exposure to sun and to high temperatures in general;
the use of a white umbrella; avoidance of alcohol and
of an excess of heating foods, and in a temperate life
in all respects. Poor health, fatigue, and violent ex-
ercise are all predisposing causes. Tropical camps
should be located in cool and well-ventilated places,
and tents should have doublé roofs.
Dengue. Dengue is a “highly infectious, febrile
disease, characterised by severe rheumatoid pains in
joints and limbs, and in some cases by a cutaneous
eruption of varying character and duration.” It is
distinctly a disease of warm climates, although it has
occurred as far north as latitude 40° in Europe and
in North America, and as far south as the southem
THE HYGIENE OF THE ZONES
201
tropic. It comes mostly in the hottest months, and
is almost always checked by cold weather. Moisture
has a subordinate influence. Dengue resembles yel-
low fever in its prevailing preference for coasts,
deltas, and large river valleys; in its relation to over-
crowding and unsanitary conditions, and in its ad-
vance along routes of travel. Dengue attacks any
race, and immunity is not secured by one attack.
There is often a recurrence.
Beri-beri. A dropsical affection, combined with a
disturbance of motion and sensation, and of heart
action, beri-beri is found prindpally in or near
the tropics, being especially common in the Malay
Peninsula, and the adjacent archipelago, where it is
often a scourge. It is especially liable to break out
among gangs of labourers. Beri-beri epidemics are
most common during the rainy season. High tem-
perature and dampness are controlling factors, as are
poor health, fatigue, privation, chili, overcrowding,
etc. Damp years are apt to be marked by the sever-
ity and prevalence of beri-beri.
Other Minor Diseases. Among the minor tropical
diseases may be named sleeping sickness, limited to
tropical Africa and almost wholly confined to the
negro; and yaws, also distinctly tropical in distribu-
tion, requiring high temperature and moisture, found
chiefly in some of the larger island groups, and prin-
cipally affecting the negro.
General Conclusions: Tropics. All parts of the
equatorial zone are not equally disagreeable or hostile,
-
202
CLIMATE
so far as occupation by the white race is concemed.
Many elderly persons and those who are overworked
may find rest from nervous tension in the enervating
climate of the tropics. The drier districts are to be
preferred to the moister, the higher altitudes to the
lowlands, coasts and islands well ventilated by pre-
vailing winds, to regions where the air is stagnant.
Much-needed relief from the heat at sea-level may
be obtained by resort to tropical mountain stations,
and many of these have become well-known health
resorts. Tropical mountain climates resemble the
climate of the temperate zones in their lower tem-
peratures and in certain other ways, but they can
never be the equivalent of a temperate zone climate,
for they lack the seasonal changes. Some tropical
climatic characteristics disappear with altitude, while
others change little. The non-seasonal character of
tropical mountain climates, the so-called “ perpetual
spring,” is not by any means the best fitted for man’s
physical and mental development, however pleasant
it may be for a time. With increase of altitude, there
is a decrease in, or a disappearance of, some of the dis-
eases which prevail near sea-level, such as malaria,
yellow fever, liver abscess, etc. When introduced
from the lowlands, such diseases are not likely to be
severe, or to spread. In their stead, however, may
come an increasing frequency of diseases which are
characteristic of high latitudes, such as rheumatism,
and heart and lung troubles. Tropical hill stations
in India show a smaller mortality among the troops
TEE EY01ENE ÓF TEE ZONES
203
than do lower levels. In India, as elsewhere in the
tropics, hill stations are beneficial in restoring those
who are exhausted by overwork or by the heat of the
lowlands. They are especially advantageous for
delicate women and children. Nevertheless, climates
which are temperate because of altitude in the tropics
cannot replace climates which are “temperate” be-
cause of latitude.
The acclimatisation of the white race in the tropics
is a question of vast importance. Upon it depend
the control, government, and utilisation of the tropics.
It is a very complex problem, and it has been much
discussed. It is complicated by the Controls exercised
by race, diet, occupations, habits of life, and the like.
To discuss it fully is impossible in this place. The
gist of the matter is this: White residents from cooler
latitudes on coming into the tropics must adjust
themselves physiologically to the new climatic condi-
tions. During this adjustment there is more or less
strain on various organs of the body. The strain
may be too severe; then the individual suffers. The
adjustment is usually much retarded and hindered by
a persistence in habits of food, drink, and general
mode of life which, however well suited to the home
climate, do not fit tropical conditions. During the
adjustment, especially if complicated by irrational
habits, the body is naturally sensitive to the new dis-
eases to which it is exposed. Even should no specific
disease be contracted, there are anaemic tendencies and
other degenerative changes. Experience teaches
204
CLIMATE
that white men cannot with impunity do hard man-
ual labour under a tropical sun, hut that they may
enjoy fairly good health as overseers, or at indoor
work, if they take reasonable precautions. Accli-
matisation in the full sense of having white men and
women living for successive generations in the tropics,
and reproducing their kind without physical, mental,
and moral degeneration,—*. ecolonisation in the
true sense,—is impossihle. Tropical disease and
death-rates, as has been abundantly shown, can he
much reduced by proper attention to sanitary laws,
so that these rates may he not much, if any, higher
than those in the extra-tropics. And with increas-
ing medical knowledge of the nature and prevention
of tropical diseases, as well as by means of modern
sanitary methods, a white resident in the tropics will
constantly become better ahle to withstand disease.
As Manson has put it, acclimatisation is less “an
unconscious adaptation of the physiology of the
individual” than “an intelligent adaptation of his
habits.” For greater comfort, for better health, and
for greater success, properly selected hill stations
will, however, always be essential to northemers who
have to live in the tropics, especially to white women
and children.
It has heen well said that the white soldier in the
tropics is “ always in campaign; if not against the
enemy, at least against the climate.” This sentence
may he made to fit the case of the white civilian in
the tropics by making it read: the white race in the
THE HYGIENE OF THE ZONES
205
tropics is always in campaign against its enemy, the
climate.
Temperate Zones: General. Far from being
temperate as regards the general climatic conditions
over much of the land area of the so-called temper-
ate zones, these beits rightly deserve their name only
in the sense that in their physiological effects they are
intermediate between the equatorial and the polar
zones. In the temperate zones the organs of the
body act more equally than in the warmer or the
cooler latitudes. In the central part of the temper-
ate zones, especially over the continents, are found
the four seasons. The winter cold is met by means
of warm clothing, heated houses, and other means of
protection. Unless too severe, or too prolonged, when
deaths by freezing may occur, the cold of a Continen-
tal winter in the north temperate zone acts as a health-
ful stimulant upon body and mind. In the tropics,
the body is unused to adjusting itself to tempera-
ture changes, because such changes are there slight,
and is readily affected by them. But the frequent,
sudden, and severe changes of many parts of the tem-
perate zone are usually borne without serious dis-
comfort or injury, if the body is in good health, and
is accustomed to adjusting itself readily to these
changes. The habit of keeping houses very warm
during the winter, and of having the air indoors very
dry, weakens the body’s power to resist the great cold
outdoors, especially if the air be damp, and causes
affections of throat, lungs, and nose. The summers,
206
CLIMATE
although hot in the lower latitudes of these zones,
and marked by spells of warm weather even to their
polar limits, are not characterised by such steady,
uniformly moist heat as is typical of the tropics.
When the heat is extreme, and the relative hu-
midity is high, night and day, sunstroke and kin-
dred affections are occasionally noted in places,
but the invigorating cool of autumn and winter are
never far off, and may always be trusted to bring
relief.
Winter and Summer Diseases. It is natural that
marked seasonal and sudden weather changes, such
as those which characterise much of the temperate
zones, especially in the northem hemisphere, should
be reflected in the character, distribution, and fre-
quency of the diseases which are found in these zones.
Diseases of the respiratory system, bronchial and
rheumatic affections, diseases that result from colds
and chills, pneumonia, bronchitis, influenza, diphthe-
ria, whooping cough, are all common in climates with
sudden marked temperature changes, especially if
those changes are accompanied by cold, damp winds.
These diseases are also most frequent in the winter
months, when the weather changes are more common
and more severe, and when, in consequence, the vital-
ity of the body is lowered and its power of resistance
against the attack of disease germs is weakened. A
greater prevalence of diseases of the respiratory or-
gans, catarrhs, and rheumatic affections in cool, moist
weather, with sudden changes, has been shown by
THE HYOIENE OF THE ZONES 207
Weber, and several investigators have found a higher
mortality after a greater variability of temperature.
Many contagious or infectious diseases, such as diph-
theria, influenza, measles, and scarlet fever, for ex-
ample, are also more common in the colder season, not
because the lower temperatures are the direct control-
ling factor, but largely because the colder weather
drives people indoors; houses and buildings generally
are less well ventilated; more clothing is worn, less
attention is paid to personal cleanliness, and there
is increased opportunity for contagion, especially
among the poorer classes. Obviously, these are in-
direct effects of meteorological conditions. Other
factors, also, must be taken into consideration. Thus
one reason why the natives of the farther north, where
the winters are very severe, suffer less from some of
the diseases which are common in warmer latitudes
is not because of the lower temperatures, but because
they are less exposed to contagion owing to less com-
munication with the outside world.
In the warmer months, fevers and diseases of the
digestive system, diarrhoea, malaria, typhoid fever,
are prevalent. Thus there are usually two maxima
of mortality: one in the colder season, when the vari-
ability of temperature is greatest, chiefly due to re-
spiratory diseases, and another in the warmer months,
largely due to infant mortality from diarrhoeal
disorders.
Tvberculosis. “ A nationally self-inflicted, un-
necessary, and preventable pestilence ”; world-wide
208
CLIMATE
in extent; found in every variety of climate, and at
all altitudes; causing from 10 to 15 per cent. of all
deaths; the scourge of the temperate zone, tuber-
culosis is, on the whole, less frequent in higher
latitudes, on mountains, and in arid or semi-arid dis-
tricts. Climate, however, is not the controlling fac-
tor in the latter cases, but sparseness of population
and infrequency of communication with the outside
world. The density of population; the social and
economie conditions; the occupations and habits of
the people,—these are important Controls. Over-
crowding amid unsanitary surroundings, absence of
sunlight, impure air, are predisposing causes.
Weather, or other conditions which decrease the vi-
tality, increase the susceptibility to tuberculosis.
Sudden temperature changes, especially with high
relative humidity at low temperatures, cause chills
and lower vitality.
Consumption, it is clear, can be successfully treated
where pure air, abundant sunshine, good food, and
outdoor exercise are to be had. The first of these
desiderata, pure air, and plenty of it, is the most im-
portant of all. It is usually found on desert, ocean,
mountain, and in forest. Hence such climates are
generally advantageous m the treatment of tuber-
culosis of various kinds. Yet climate is no longer
believed to play as important a róle in the matter
as was formerly assigned to it. Good hygiene has
to a large extent replaced climate. A health resort
THE HYGIENE OF THE ZONES 209
where a patiënt can find comfortable quarters, con-
genial company, plenty of diversion, and where
favourable climatic conditions, such as abundant sun-
shine, absence of disagreeable winds, dust, and sudden
weather changes, encourage outdoor life, is to be
recommended. The climate does not cure; it is an
important help in the treatment of the disease. Some
patients, especially elderly people and those suffer-
ing from nervous, cardiac, or bronchial affections,
fare better at lower altitudes; but higher altitudes,
with the stimulating effects, deep respiration, and ac-
tive use of the lungs which they induce, often offer
many climatic conditions favourable to outdoor life
and hence of great benefit in the treatment of the
disease. The dry, pure air and abundant sunshine
of many of the well-known mountain health resorts
are very favourable climatic helps. Moreover, the
smaller temperature ranges of mountain and marine
climates are also helpful. In many, if not in
most cases, any change of climate is beneficial, but
especially so if such a change is accompanied by the
favourable conditions just enumerated. Ocean air,
although damp, is beneficial to many patients because
of its purity, its salinity, and its small temperature
ranges. Hence an ocean voyage, with its relief from
unsanitary or harmful occupations, may be an ex-
cellent restorative. Results obtained in the treat-
ment of tuberculosis by climatic change vary through
a wide range. The reasons for such discrepancy are
210
CLIMATE
to be sought in the difference in the stage of the dis-
ease treated, and in the habits, food, and mode of life
of the patients.
Pneumonia. Pneumonia is found almost every-
where, in the tropics probably quite as conunonly as
in colder latitudes, and at high altitudes as well as at
sea-level. A greater frequency of pneumonia gen-
erally follows cold, damp weather, with marked
changes of temperature, which lower the vitality and
are conducive to chills. Hence the disease is most
prevalent in the colder months. Among the predis-
posing causes, physical weakness following other dis-
eases is potent, as are mal-nutrition and similar
debilitating agencies. Severe cold spells are likely
to he followed by an increase of pneumonia, espe-
cially among elderly persons and children. Negroes
who have gone to cold climates are very subject to
the disease.
Diphtheria. Although geographically widely dis-
tributed, diphtheria is chiefly a temperate zone dis-
ease, occurring sporadically or epidemically, however,
in tropics and polar latitudes. Like other infectious
diseases of the temperate zone, diphtheria is most
frequent in the colder months, because the conditions
of life are then most favourable to contagion, and
because vitality is then most lowered by the prevail-
ing weather conditions. Diphtheria is more common
at low altitudes than high.
Influenza. The well-known disease, “grippe,”
caused by a specific organism discovered in 1892, is
THE HYGIENE OF THE ZONEB
211
occasionally very serious, and is apt to be closely
followed by epidemics of pneumonia and other dis-
eases of the respiratory organs. Although very
carefully studied, there is no certain evidence of any
influence of weather, climate, or soil upon the disease.
The last great epidemie of influenza, in 1890 and
thereabout, is believed by Assmann to have been
associated with dry spells and with the carriage of
dust. The worst outbreaks have been in the colder
season, when indoor life, less fresh air, and overcrowd-
ing would naturally help to spread the contagion.
The fact that those who are suffering from influenza
are often not kept indoors explains a general spread
of the disease.
Bronchitis. Bronchitis is most common in the
higher latitudes, and in the cold months, when the
temperature is low and when sudden and rapid varia-
tions of temperature are frequent. Dust, blown from
the dry surface of streets and the like, helps to irritate
the throat and nasal passages. Belief from bron-
chitis may be found where the climate is warm and
uniform; the air soft and balmy; where there are no
irritating winds driving the dust to and fro, and
where sunshine is abundant.
Rheumatism. Rheumatic affections are, as a whole,
more common in colder than warmer, and in damper
than drier climates, but may be classed under the
temperate zone. Exposure to cold and wet, bring-
ing on chills, and sudden temperature changes, es-
pecially in damp climates, while not the cause of
212
CLIMATE
rheumatism lowers the vitality in such a way that the
specific cause may assert itself. In many cases a
change of altitude makes no difference whatever; it
may, in fact, aggravate the trouble.
Measles and Scarlet Fever. Both measles and
scarlet fever are independent of weather and climate,
except in so far as the colder, more inclement, months
involve an unhealthier mode of life, with less atten-
tion to sanitary measures. A maximum is usually
found in the colder months, when infection is most
likely. Measles occurs in all climates, but usually
most commonly and most severely in temperate lati-
tudes. Scarlet fever is essentially a disease of the
temperate zone. Isolation from sources of infection
is more important than any climatic control in these
diseases, which show very various relations to season,
altitude, and race.
Typhoid Fever. Typhoid fever is found in al-
most all parts of the world. Although common in
the tropics, being one of the most generally fatal
diseases there, especially among recent European
arrivals, it is not, according to Manson, properly
classified as a tropical disease. It is very prevalent in
the temperate zone, having a maximum frequency in
late summer and autumn, and is certainly largely
preventable by good sanitation and pure food and
water. The germs of typhoid fever are killed in a
few hours under direct sunshine, and their growth is
slow even in diffused daylight. The well-known
studies of Pettenkofer, at Munich, showed an inverse
TEE BYÖIENE ÓF TEE ZONES
213
relation between the ground-water level and the pre-
valence of typhoid, but this appears not to he a
universal relation. The view formerly held regard-
ing a connection between temperature and humidity
and typhoid epidemics has now generally been
abandoned.
Whooping Cough. Whooping cough is more
prevalent in temperate and cooler climates, where the
temperature changes are marked and where the
respiratory organs are most affected, and is rare and
less severe in warmer latitudes. But the absence of
whooping cough is doubtless often to he explained
on the ground that it has not been imported, rather
than on any direct climatic basis. Although com-
moner and more severe in the cooler months, epi-
demics may occur at all times, without relation to
altitude. Croup, also, prevails chiefly in damp, cool
weather, with sudden changes.
Cholera Infantum. Among the summer diseases
of the temperate zone, cholera infantum occupies a
very prominent place. It increases with rising, is at
a maximum with maximum, and decreases with fall-
ing, temperatures. The greater and more continu-
ous the heat, the more general is the disease. Cool
spells check it immediately. It is more common in
the overcrowded and overheated quarters of the city
than in the country, and may be greatly checked by
the use of pure milk and fresh food.
Hay Fever. The specific cause of hay fever has
been much debated, but is generally regarded as
-
214
CLIMATE
vegetable pollen of some sort. The particular kind
of pollen may differ in different cases. The irrita-
tion is naturally confined to the season of plant'
growth. Belief may generally be secured by seek-
ing a higher altitude, where the cause of irritation is
absent, and where the air is pure and dean. Sea
voyages, also, are beneficial.
Polar Zones: General. The north polar summer,
as has been- pointed out, in spite of its drawbacks, is
in some respects a pleasant and healthful season.
But the polar night is monotonous, depressing, re-
pelling. Parry said that it would be difficult to con-
ceive of two things which are more alike than two
polar winters. An everlastingly uniform snow cov-
ering, rigidity, lifelessness, silence—except for the
howl of the gale or the cracking of the ice. Small
wonder that man feels like an intruder. Small won-
der that the polar night has sometimes unbalanced
men’s minds. Extraordinarily low winter tempera-
tures are easily bome if the air be dry and still. Nan-
sen notes “ not very cold ” at a temperature of — 22°,
when the air was still. Another Arctic explorer, at
— 9°, says “ it is too warm to skate.” Zero weather
seems pleasantly refreshing if clear and calm. But
high relative humidity and wind—even a light breeze
—give the same degree of cold a penetrating feeling
of chili which may be unbearable. Thus the damper
air of spring and summer usually seems much colder
than the drier air of winter, although the temperatures
may be the same. Large temperature ranges are
THE HYGIENE OF THE ZONES
215
endured without danger in the polar winter when the
air is dry. When exposed to direct insolation, the
skin bums and blisters; the lips swell and crack. In
severe cold the vitality of the body is lowered, the
pulse slackened, and the ability to bear.hardships de-
creased. The surface of the body cools first; the
blood circulates more slowly; the surface blood-ves-
sels contract, and the blood then becomes intemally
congested; the lungs and heart may be affected, and
in extreme cases death results. The danger of freez-
ing is naturally greatest in the case of the hands, feet,
ears, and nose, which are most exposed and can least
well be kept warm. The skin may swell, become
thick and hard, and break open. The power of re-
sistance to extreme cold depends on the physical con-
dition, clothing, food, exercise, exposure to sunshine,
dampness, wind, and other factors. The feeling of
cold is increased by hunger, and rheumatic people
usually suffer most.
The physiological effects of polar cold and dark-
ness have been fully reported upon by Arctic and
Antarctic explorers. The recent expeditions, on
which very careful attention has been given to pick-
ing the men, as well as to their health, diet, exercise,
and general hygiene, have shown much less marked
effects than did the earlier expeditions. Among the
effects which have often been observed are a weaken-
ing of the senses of taste and of smell, as a result of
congestion and over-secretion on the mucous mem-
branes; depression, apathy, and sleepiness, often
216
CLIMATE
followed by nervous excitement and even in some
cases by insanity; anaemia; tendency to digestive dis-
orders and dyspepsia; constipation or diarrhoea;
greatly lessened perspiration; fading of hair and
beards; change of colour of the skin to pale and yel-
low; a lowering of the body temperature. The mo-
notony of the polar night is depressing to a degree.
Thirst has heen one of the greatest plagues of
Arctic explorers in the past. The result of a large
evaporation from the lungs into the dry, cold air,
thirst is a characteristic of the deserts of snow and
ice as it is of the deserts of sand. The relief of this
thirst hy eating snow is dangerous, for it leads to
inflammation of the throat and to digestive and bowel
troubles. Moreover, such relief is but tèmporary.
It has heen pointed out by Dr. F. A. Cook that,
like the polar animals, the Eskimos can withstand long
periods without food; that their intestinal capacity
is increased in such a way that they can assimilate a
constant meat diet, and that they are protected
against the cold by thick, fatty tissues and by their
profuse peripheral circulation.
Life is hard in the polar zones. Deaths hy drown-
ing in gales at sea, hy freezing, and in snowstorms
are frequent. Yet, on the other hand, most of the
diseases which have been discussed in this chapter are
rare or absent in the far north. There is a remark-
able infrequency of infectious diseases. Polar air is
very free from micro-organisms—a fact which is due
chiefly to lack of communication with other parts* of
THE HYGIENE OF THE ZONES
217
the world; colds are reported as rare or unknown, al-
though changes of temperature are often frequent
and large. The summer sun, both by direct and by
reflected radiation, bums and bronzes the skin, and
may cause snow-blindness. An Arctic summer, with
its long days, crisp, clean air, and sunshine, offers
conditions which are doubtless excellent for many
nervous and gastric troubles, and one may predict a
considerable development of summer resorts within
the Arctic circle for the pleasure-loving, wealthy, and
unoccupied persons of the north temperate zone.
Scurvy. Scurvy has been considered a polar dis-
ease par excellence, because it has, in the past, been
prevalent on Arctic expeditions, and is found to-day
in northem latitudes. Scurvy is, however, known
also in many other parts of the world. It is found
under conditions of overcrowding, and of poor ven-
tilation, which are natural consequences of extreme
cold. Cold is not the cause of the disease, for scurvy
is found in warm countries also; but rigorous climatic
conditions, poor food—especially the lack of fresh
vegetables, over-exertion, depression, lowered vi-
tality by exposure to cold, etc., are predisposing
causes. The best preventives of scurvy are good
food, an active outdoor life, and mental stimulation.
With these precautions and good hygiene, 'scurvy has
almost disappeared among civilised nations.
Climate and Health: General Conclusions. The
old view conceming the paramount influence of cli-
mate upon health is being replaced by the view that
218
CLIMATE
good hygiene is of more importance than climate
alone. Medical Science has done much to stamp out
some diseases like small-pox, and it will in time prob-
ably largely stamp out others, like malaria, or yellow
fever, or even tuberculosis and diphtheria. Man
himself, not climate, is being held responsible for the
occurrence of this or that disease or epidemie, for its
distribution, and for the death-rates resulting from
it. Man has lowered the death-rate from disease
most wonderfully. He can lower it still further.
Vaccination for small-pox; preventive inoculation for
plague; antitoxin for diphtheria; good food, pure air,
and exercise for scurvy; draining swamps 'and pools
and the use of mosquito netting for malaria; pure
water for cholera, typhoid fever, and dysentery—
these are but a few of the methods now employed by
man in his war against disease.
The influence of climate is by no means to be dis-
carded as of no account, for that it acts, in many
ways, both directly and indirectly, has been shown in
this chapter. The newer view regarding the influence
of a change of climate as a preventive, or restorative.
is that a change of residence, habits, occupations, food,
is usually of more importance than the change in
atmospheric conditions. If pure air, good food, free-
dom from worry, time for rest, proper exercise, out-
door life, and a congenial occupation are provided,
many bodily and mental ailments will yield to the
treatment. Climate is to be considered, because it
affects our bodily comfort; it may be dull, rainy, and
THE HYGIENE OF THE ZONES
219
cheerless, or bright, sunny, and exhilarating; it may
tend to keep us indoors, or it may tempt us
to go out. Thus some climates will naturally be
avoided, and others sought out, and the choice of a
suitable climate will depend upon the disease to he
dealt with. As a recent writer has well said, climate
may “ play an important part in the curative process,
but the climate of certain localities does not possess
any peculiar properties which act as a specific on cer-
tain diseases.”
CHAPTER VIII
THE LIFE OF MAN IN THE TROPICS
Climate and Man: General—Some Old Views Regarding the Effects
of Climate on Man—Factors in the Problem Other than Cli-
mate—Climate and Habitability—The Development of the
Tropics—The Labour Problem in the Tropics—The Govern-
ment of Tropical Possessions—Primitive Civilisation and the
Tropics—Dwellings in the Tropics—Clothing in the Tropics—
Food in the Tropics—Agriculture, Arts, and Industries in the
Tropics—Some Physiological Effects of Tropical Climates—
The Equatorial Forests—The Open Grass-Lands of the
Tropics: Sa vannas—Trade Wind Beits on Land: the Deserts
—Trade Wind Beits at Sea—Monsoon Districts—Tropical
Mountains.
Climate and Man: General. Man’s climatic en-
vironment affects him in many ways. His clothing,
dwellings, food, occupations, and customs; his physi-
cal and mental characteristics; his systems of gov-
emment; his migrations; his history—all are affected
to a greater or less degree.
Civilised man protects himself more or less suc-
cessfully against unfavourable climatic features.
Thus, there is a gradual transition from the primitive
shelter made of branches of trees, of skins, or leaves,
to the permanent and highly elaborate modern build-
ing, which is both heated and cooled artificially. The
building materials; the methods of uniting these ma-
220
THE LIFE OF MAN IN THE TROPICS 221
terials, as by braiding, or binding, or by the use of
mortar, usually show the control of climate. More-
over, the material often determines the general plan
of the building. There is also the transition from the
primitive and scanty clothing made of leaves or bark
where trees grow, or the skin of an animal where
trees are lacking, or warmer clothing is needed, to the
manufactured and perhaps imported garment of
wool, or cotton, or silk. Again, there is the increas-
ing variety of food, from that of primitive man, sup-
plied directly where he lives, to the highly varied diet
found in a civilised community to-day, to which dis-
tant latitudes are made to contribute their local
delicacies.
All these changes man has brought about. But he
cannot change his climate. Slight local modifica-
tions may be secured here and there, as by planting
trees to serve as wind-breaks, or perhaps by in-
creasing the relative humidity a little through the
construction of an artificial reservoir. No such modi-
fïcation is possible in man’s climatic environment as
has been accomplished on the surface of the land un-
der human agency. The atmosphere is as essentially
unalterable as it is all-pervading. When we see how
plants and animals are affected by atmospheric con-
ditions, it is not unreasonable that we should expect
man to show effects of a similar kind. 1
Some Old Views Regarding the Effects of Climate
on Man. It is, however, easy to go too far in calling
upon climate to explain phenomena which we may
222
CLIMATE
otherwise find it difficult to account for. This was
the mistake formerly made by many writers on this
subject, as has been clearly pointed out by Ratzel in
his Anthropogeographie, where he gives an outline
of many of these earlier views. Maupertius and
others held that the colour of man’s skin becomes
paler with increasing distance from the equator.
Livingstone wrote that in Africa religious ideas also
seemed to depend on distance from the equator. One
writer held that cold produces a small stature; an-
other believed that the Pygmies are small because of
the heavy seasonal rains which fall in hot equatorial
Africa. Climate was believed to explain the over-
hanging eyebrows and partly-closed eyes of the ne-
gro; the small eyes and beardless faces of the Chinese;
the (supposed) fact that more twins were bom in
Egypt than elsewhere. And so on. The broad
generalisations of Montesquieu, Voltaire, Buffon,
Hume, Buckle, and others, furnish interesting read-
ing, and contain much that is suggestive and in-
structive, but they usually carry us well beyond the
range of reasonable probability. Even Hippoc-
rates’s observations on climatic Controls are not
without value to-day.
Factors in the Problem Other than Climate. To
most of these older writers climate meant more than
it does to-day. It included much of what is nows
termed our whole physical environment. Moreover
they based their conclusions upon incomplete records,
covering far too short periods of time. It must be
THE LIFE OF MAN IN THE TROPICS
223
remembered that we are dealing here with large,
important, highly complex phenomena. Man moves
readily from place to place, from climate to climate.
His food, drink, habits, occupations; to some extent
his physical and mental characteristics, change in
consequence. Inheritance, intermarriage, environ-
ment, opportunities, soil, and many other factors
enter in to determine what changes individual man and
the race as a whole shall undergo. Time is a very im-
portant element in the final result, for in time a
gradual adaptation to new conditions takes place.
Climate is but one of many Controls, albeit a most
important one, for it largely determines what many
of the other factors, such as diet, customs, and occupa-
tions, for example, shall be. The task of giving
climate its proper place as a factor controlling the
life of man as a whole is a difficult one, which cannot
be definitely and satisfactorily solved to-day, or
to-morrow.
It would take us far beyond the limits set for our
present volume were we to attempt any consideration
of the many complex problems in connection with the
possible influences of climate upon the physical and
mental characteristics of man. Investigations along
these lines have given rise to much debate. It is our
present purpose merely to point out some of the more
simple and obvious ways in which the life of man is
controlled by climate. This control, it should be ob-
served, is either direct, where physical and mental
changes under climatic stimulus are concemed, or
224
CLIMATE
indirect, as when climate acts upon man through its
influence over the distribution of the animals and
plants upon which man depends for his food, cloth-
ing, and materials of various kinds.
Climate and Habitability. Climate determines
both how and where man shall live. It classifies the
earth’s surface for us into the so-called habitable and
uninhabitable regions. The deserts of sand and the
deserts of snow and ice, whether the latter be near sea-
level or high up on mountain tops, are alike climatic,
the former because of aridity; the latter because of
cold. The only non-climatic deserts are recent lava-
flows. Where a soil is present which is not frozen
for much over half the year, and where there is
reasonable temperature and sufficiënt rainfall, plants
and animals are found, ranging from few and lowly
forms where conditions are the hardest and where
all organic life is especially adapted to these condi-
tions, to the greatest abundance where conditions are
most favourable.
Man is influenced by much the same Controls as
those which affect plants and the lower animals.
From the highest latitudes he is excluded by cold.
The higher altitudes are hostile both because of cold
and of diminished pressure. The deserts qf sand are
uninhabited, or thinly populated, by reason qf aridity.
Forests, where rainfall is abundant, are unfavourable
to a dense population. The trees must be cleared
away bef ore settlement is easy. Man is widely dis-
tributed over the earth’s surface. In his migrations
THE LIFE OF MAN IN THE TROPICS
225
he has carried with him, beyond their original limits,
many plants and animals. Ratzel points out that
the coldest place in the world in January is a large
Siberian city, Verkhoyansk, while one of the hottest
places in the world is Massowa, on the Red Sea, the
Capital of the Italian colony of Eritrea. But the life
of man is harder here and easier there, according to
climatic conditions and the scarcity or abundance of
plant and animal life.
Man is distributed in great beits around the world,
corresponding roughly to the broad zones of vege-
tation, desert, steppe, and forest, the limits of which
are set by temperature and rainfall, but man is much
more dependent on rainfall than upon temperature.
Water he must have, directly from the plouds, or in-
directly through rivers, or springsr-or^wells, or from
melted snow and ice. There^are certain common
conditions of life which afféct the people who live in
the same zone in the sazóe broad, general way, just as
these zones have similar general conditions of winds
and of rainfall. This, as Ratzel has pointed out,
means that there is a climatic factor at work to main-
tain differences between the people of different zones,
in spite of the great movements which are constantly
tending to produce uniformity. Obviously, the dif-
ferences in the life of man which depend upon climate
will be most noticeablè, and will be likely to have the
greatest historical significance, when marked differ-
ences of climate are found dose together, as in the
case of mountain ranges like the Alps, or of a pro-
IS
226
CLIMATE
nounced lowland, plateau, and mountain topography
like that of Peru or Mexico.
All the regions of sparse population are gradu-
ally being encroached upon by an invasion from their
borders. Forests are being cleared and replaced by
open agricultural, lands. Wheat and corn are re-
placing grass on the steppes and savannas, especially
where irrigation can be practised. Deserts are being
redaimed for farming here and there where water
is available. The more civilised man becomes, 4he
denser the population which the different parts of the
earth can be made to support. From the wandeling
hunting and fishing tribes of the African forest or of
the borders of the Arctic sea, through the farming
populations of the cleared forest and of the steppe,
to the crowded industrial centres of the modem city,
there is such a gradation. It is the story of a more
complete to a less complete mastery of man by his
environment. But in spite of all that man can do,
the larger climatic limitations persist. The Green-
land desert of snow and ice, and the Saharan desert of
sand, must remain practically deserted.
The Development of the Tropics. Within the
tropics, under the equatorial sun, and where there is
abundance of moisture, animal and plant life* reach
their fullest development. Here are the lands which
are most valuable to the white man because of the
wealth of their tropical products. Here are the
tropical “ spheres of influence ” or “ colonies ” which
are among his most coveted possessions. It is in this
THE LIFE OF MAN IN THE TROPICS
-
227
belt that food is provided for man throughout the
year without labour on his part; in which frost and
drought need not be feared; where shelter and cloth-
ing are so easily provided, and often so unnecessary,
that life becomes too easy. Nature does too much;
there is little left for man to do. The simplicity of
life, so far as providing food is concerned, has been
emphasised by many writers. We are told that three
bread-fruit trees furnish enough food for one man;
that a labourer needs only twelve bananas for his
daily food; that one day a week is enough time to
spend in caring for a manioc plantation; that two
days’ work a week is often enough to enable a man to
support a family; that a month’s labour will provide
for a Malay more sago than he can use in ajear, etc.
Stories are told of shipwrecked seamen in the tropi-
cal Pacific who lived for many days on one cocoanut
a day for each man. Captain Cook put the case very
emphatically when he said that a South Sea Islander
who plants ten bread-fruit trees does as much to-
wards providing food for his family as does a man in
northem Europe who works throughout the year.
In a debilitating and enervating climate, without
the necessity of work, the will to develop both the
man who inhabits the tropics, and also the resources
of the tropics, is generally lacking. Voluntary pro-
gress toward a higher civilisation is not reasonably
to be expected. The tropics must be developed un-
der other auspices than their own. “ Where nature
lavishes food and winks at the neglect of clothing and
228
CLIMATE
shelter, there ignorance, superstition, physical prow-
ess, and sexual passion have an equal chance with
intelligence, foresight, thought, and self-control.” 1
There is no superfluous energy for the higher
things of life. Thus it has come about that the na-
tives of the tropics have the general reputation of
being indolent and untrustworthy; of always being
ready to put off until “ to-morrow.” Obviously, no
such sweeping generalisation is to .be taken too liter-
ally, for the lower latitudes have produced many men
far from deficiënt in physical and intellectual power.
Moreover in those parts of the tropics where natural
conditions are more severe, the natives are usually
more industrious. But it is true that the energetic
and enterprising races of the world have not devel-
oped under the easy conditions of life in the tropics.
As Edward Whymper’s Swiss guide said of the na-
tives of Ecuador, “ it would be good for tropical
peoples to have a winter.” Guyot has put the case in
this way:
A nature too rich, too prodigal of her gifts, does not
compel man to snatch from her his daily bread by his daily
toil. A regular climate, the absence of a dormant season,
render forethought of little use to him. Nothing invites him
to that struggle of intelligence against nature which raises
the forces of man to so high a pitch, but which would seem
here to be hopelcss. Thus he never dreams of resisting this
all-powerful physical nature; he is conquered by her; he sub-
mits to the yokc, and becomes again the animal man,—for-
getful of his high moral destination»
The movements of the body, the habit of carrying
'John R. Commons, The Ckautauquan, May, 1904, p. 222.
THE LIFE OF MAN IN THE TROPICS 229
loads on the head, even the native dances, have been
thought by some to show the enervating effects of the
climate. One writer has even gone so far as to see
similar effects in the domestic animals, which he be-
lieves to be more docile than those in extra-tropical
latitudes.
The Labour Problem in the Tropics. “What
possible means are there of inducing the inhabitants
of the tropics to undertake steady and continuous
work, if local conditions are such that from the mere
bounty of nature all the ambitions of the people can
be gratified without any considerable amount of
labour? ” In these words, Alleyne Ireland well sums
up the labour problem in the tropics. If the natives
are, on the whole, disinclined to work of their own
accord, then either forced native labour, which is con-
trary to the spirit of the times, or imported inden-
tured labour, becomes inevitable if the tropics are to
be developed. With few exceptions, and those where
the pressure of a large population necessitates labour,
effective development has been accomplished only
where imported Chinese, Japanese, or coolie labour
has been employed, under some form of contract.
Negro slavery began in the West Indies, under early
Spanish rule, and its perpetuation was certainly in
part aided by climatic Controls. The best develop-
ment of many tropical lands depends to-day upon
Chinese labour. It will be so in the Philippines. In
Java, Holland has succeeded by forcing the natives
to work. ^
230
CLIMATE
With a large native class which is indolent, work*
ing intermittently for low wages, or which is bound
under some form of contract, it follows that the na-
tive or imported labouring classes are separated by a
broad gulf from the upper, employing class, which is
usually essentially foreign and white. The latter
class tends to become despotic; the former, to become
servile. Marked social inequalities thus result, ac-
centuated by the fact that the foreign-born white is
usually debarred from all hard labour in a hot tropi-
cal climate. White labourers are not likely to be-
come dominant in the tropics for two reasons:—first,
because the climate is against them; and second, be-
cause the native is already there, and his labour is
cheaper. White men are not doing the hard daily
labour of India, or of Java, or of the Philippines, or
even of Hawaii. They are directing it.
The Government of Tropical Possessions. The
govemment of European possessions in the tropics
has thus far been determined chiefly by three con-
siderations: (1) The general incapacity of the na-
tives, through ignorance, or lack of interest, or
their undeveloped condition, to govem them-
selves properly. (2) The fact that the white resi-
dents are generally comparatively few in number and
are only temporarily in the country, to make money
and then to go home again. The white population
is often composed chiefly of men—soldiers, officials,
merchants, adventurers. There is little inducement
to found permanent homes. (3) The marked class
THE LIFE OF MAX IN THE TROPICS
231
distinctions already referred to. These generalisa-
tions must obviously not be carried too far.
Hawaii, very favourably situated as regards climate,
will in time become an American State, and Brazil,
most of whose immense area is typically tropical, has
an increasing European immigration of permanent
settlers. But what has been said is, in the main, true.
The white residents constitute a caste, and naturally
become the rulers, the home govemment retaining
general control, often by force of arms. The native
population, although largely in the majority, may
have little or no voice in its own government. This
is clearly not a democracy. It thus comes about that
the tropics are governed largely from the temperate
zone; the standards, ideals, motives, come from an-
other land. And where governed under their own
auspices, as independent republics, the success has not
been great. Buckle first strongly emphasised the
point that hot countries are conducive to despot-
ism and cold countries to freedom and independence;
and James Bryce has recently clearly set forth the
climatic control of govemment in an essay on “ Brit-
ish Experience in the Govemment of Colonies ”
(Century, March, 1899, 718-729). The very Euro-
peans who exercise the controlling power in the trop-
ics, themselves tend to become enervated if they live
there long; they lose many of the standards and
ideals with which they started; they not uncommonly
tend to fall towards the level of the natives rather
than to raise the standards of the latter. The pecu-
232
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liar situation which may arise from the govemment
of a tropical possession in which the white race does
not become acclimated has been emphasised by Dr.
Goldwin Smith in a recent discussion of British rule
in India. “ British Empire in India,” he says, “ is in
no danger of being brought to an end by a Russian
invasion. It does not seem to be in much danger of
being brought to an end by internal rebellion. Yet
it must end. Such is the decree of nature.' In that
climate British children cannot be reared. No race
can forever hold and rule a land in which it cannot
rear its children.” The future of tropical possessions
and “ spheres of influence ” offers many problems of
great complexity, the solution of which is largely con-
trolled by the factor of climate.
Primitive Civilisation and the Tropics. There are
reasons for thinking that primitive, pre-historic man,
in his earliest stages, when most helpless, was an in-
habitant of the tropics; that he lived under the mild,
uniform, genial climate of that zone, where food was
easily obtained and protection against the inclemen-
cies of the weather least necessary. There has been
a belief that southem Asia, bordering on the Indian
Ocean, with its numerous bays, was probably the
cradle of humanity. Civilised man is believed by
many to have appeared first on the delta formed at
the head of the Persian Gulf by the Tigris and Eu-
phrates rivers, where also wheat was very likely first
grown. Ancient civilisations seem to have developed
in the drier portions of the tropics, where irrigation
THE LIFE OF MAN IN THE TROPICS
233
was necessary in order to insure abundant and regu-
lar crops, and where lived races more energetic and
more hardy than those of the damper and rainier por-
tions of the tropics, with more luxuriant vegetation.
As Professor Hilgard1 has well said:
It is hardly doubtful that the ancient ‘ Kulturrölker *
recognised these advantages (of irrigated lands) by experi-
ence,'and eschewed the laborious task of rendering cultivable
the comparatively infertile, or, at least, readily exhausted,
lands of the forest regions. . . . And it is also clear that,
inasmuch as the establishment and maintenance of irrigation
canals necessarily involve coöperation, and therefore a rather
high degree of social organisation, the conditions of the arid
regions were exceptionally conducive to the establishment of
the highly complex polities of which the vestiges are now be-
ing unearthed in what we are in the habit of calling deserts.
Civilisation was thus probably first developed,
not where the overwhelming superabundance of
nature’s gifts seems to offer the best conditions,
but where man was under some stress of labour,
some spur to effort, in less favourable natural
conditions, but such as developed him. Within
the tropics, the greatest progress later came, not on
the damp lowlands, but on the less fertile plateaus of
Mexico and of Peru, where the Aztecs and Incas
made their marvellous progress in the drier, cooler,
and more rigorous climates of altitudes over 7000 or
8000 feet above sea-level. Ratzel has pointed out,
1E. W. Hilgard: "The Causes of the Development of Ancient
Civilisations in Arid Countries/’ No. Amer. Rev.9 vol. 175, 1902,
p. 314.
234
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in the case of the mins found on the lowlands of
Yucatan and of farther India, that when such build-
ing operations are carried through by the autocratie
rule over a subject class, the situation is very different
from that in which we see spontaneous action on the
part of a whole people.
The nations living in ease on the tropical lowlands
were naturally, from early days, the object of fre-
quent attacks and invasions at the hands of the more
active and more warlike races living in more rigorous
climates farther north, or at greater altitudes on
mountains or plateaus. The invading tribes, having
in time become enervated by an easy existence on the
warm lowlands, have themselves often been later
overcome by a new enemy from the north. Some of
the greatest migratory movements in history have
taken place from colder to warmer climates, as part
of this general equatorward tendency in both tem-
perate and tropical zones. The barbarous tribes
broke through the northern passes and descended onto
the more genial and more fruitful lowlands of India,
being helped to do this by the ease of the descent.
Such mountain systems as the Himalayas, or the
Alps, stretching east and west, are natural climatic
divides between more genial and more severe cli-
mates, and have often been crossed by invading arm-
ies from the north. The descent of the Aryans into
India; the Manchurian conquest of China; the in-
vasions of Greece and Italy from the north; the
southward movement of Toltecs and Aztecs in Mex-
THE LIFE OF MAN IN THE TROPICS
235
ico, have been cited as illustrations of this equator-
ward tendency. In the southem hemisphere, it has
been suggested that the Kaffirs have shown the same
tendency—there northward,—as did the native Pata-
gonians in their predatory expeditions to the north.
The equatorward tendency may be seen to-day in
the extension of European “ spheres of influence,”
especially in Africa, the object now being essentially
a mercenary one, and not a seeking for new homes in
a more genial climate.
Dwellings in the Tropics. Dwellings, clothing,
and food are easily provided in the hot climates of
the moist tropics. In the deserts and on the moun-
tains the conditions of life are harder. The protec-
tion that is needed against sun and rain, and the
lowered temperatures of the tropical night, is usually
very simple. Man spends most of his life outdoors.
The building materials are ready at hand and simple.
Many of the primitive native huts are loosely made
of bamboo or other pliable trees, where such are
available (e. g., the mimosa used by the Hottentots);
of palm and cocoanut leaves, sugar-cane, or grass.
Pointed roofs, supported on poles, and wooden
frames with mats for walls, are a characteristic style
of architecture. In some places temporary huts are
made of skins, while more permanent dwellings are
better built, with good roofs. The permanent dwell-
ings in tropical cities are oftenest built of stone, with
thick walls. The old Spanish and Portuguese idea
was also to have narrow streets, in order that the sun-
236
CLIMATE
light might be shut out as much as possible. In the
newfer portions of tropical cities, however, wide
streets and fine boulevards are being laid out. In
the modern houses built for European residents in
the tropics, the rooms are large, airy, and well venti-
lated; there is a minimum of furnishings; there are
broad verandas with sereens for protection against
the sun; there is a proper air space between roof and
ceiling. Stoves and fireplaces for heating purposes
are unnecessary, and the absence of chimneys on the
tops of city houses has often attracted the attention
of neweomers from colder latitudes. Nevertheless,
in some places the natives are so sensitive to the
noctumal cooling that they keep themselves warm by
fires at night. Much difficulty is experienced on
account of the destructive action of ants and other
insects, and of the dampness, as well as of sudden
tropical rains and floods. Even in dry climates,
buildings do not last well, unless built of stone. As
the prevailing winds are easterly, the eastern quarters
of the cities are usually the more desirable and the
more fashionable, and are therefore inhabited by the
wealthier classes. It is the habit of those who live
in the tropics to stop work and stay indoors during
the hottest part of the day. Business is done in
moming, or later afternoon, and the afternoon siësta
has become a characteristic of the people. The late
afternoon is the time for the fashionable outdoor life
in the park, on the promenade, or at the club.
THE LIFE OF MAN IN THE TROPICS
237
Clothing in the Tropics. The clothing of the na-
tives of the tropics is of the simplest kind, often so
scanty as hardly to be called clothing at all.
In the moister portions it not infrequently consists
solely of aprons made of grass, leaves, bark, or
reeds. The children generally go naked. Where
the diurnal temperature changes are marked, heavier
clothing is usually wom at night. The clothing of
Europeans and Americans is loose and light in colour
and weight, but thin woollens are by no means to be
discarded altogether, for they are useful during the
cooler evening hours. Light headgear, for protec-
tion against the sun, such as wide-brimmed straw
hats or pith helmets, sun umbrellas, and low shoes
are used. Great care has been taken to devise the
most suitable uniform for white troops in the tropics,
even down to the most minute details of equipment.
The kind of material, the number and cut of the dif-
ferent garments, even the best kind of belt and
shoulder-straps, have received attention. Campaign-
ing in the tropics is very different from ordinary ser-
vice in the temperate zones, and all these details need
care. It is the general opinion that a loose,
light uniform, of porous material, with a minimum of
straps, beits, and pouches, is the best. As to ma-
terials, khaki has come into extensive use and is very
popular. “ Keep the head cool and the abdomen
warm” is the best rule for white resident» of the
tropics to follow.
238
CLIMATE
Food in the Tropics. Fruits, especially the ba-
nana, cocoanut, and bread-fruit, and rice, manioc,
yams, sago, and sugar-cane are staple articles of food.
Meat and fish are not much used. In the deserts the
date-palm is an important article of food, and where
irrigation is practised a variety of cereals and fruits
is usually grown. Of late years, much attention has
been paid by military officials to the question of the
best ration for white troops who serve in the tropics.
The general feeling' is that a light diet consisting
chiefly of fruit, vegetables, and cereals, with a mini-
mum of nitrogenous, heat-producing foods, is the
most likely to keep the men in good health. A light
midday meal is recommended. There are, however,
those who hold that the prevailing anaemic condition
of the tropical natives is largely due to the deficiency
of meat in their diet, and who therefore urge that
meat should be eaten in reasonable quantity.
There is much difficulty in preserving perishable
food-products. Such articles sent from cooler lati-
tudes for use in, or for transportation across, the
tropics, need special protection, by refrigeration or
quick carriage. The increase of transportation by
steam in place of sail, and the opening of the Suez
Canal, have both been factors of importance in meet-
ing this difficulty. It is distinctly an advantage for
a country to sell its food products to other countries
on its own side of the equator. Frozen meat,
carried long distances by sea across the tropics, is
not as good as fresh meat, and is also poorer than
-
THE LIFE OF MAN IN THE TROPICS 239
meat carried at sufficiently low temperatures to pre-
serve, without actually freezing it. The need for
preserving perishable food has led to an increasing
demand for ice, and hence to the multiplication of
artificial-ice plants. Recently there comes a demand
from one tropical country (India) for refrigerator
cars for the transportation of milk.
Agriculture, Arts, and Industries in the Tropics.
The need of labour in order to procure a good return
from the ground is so slight that agriculture has not
yet made much progress in the tropics as a whole.
Where frost need not be feared, where crops ripen all
the year around, and where the soil is rich with de-
caying vegetable matter, agriculture is naturally
slow to improve. Yet there are native peoples who
have advanced much farther than might be expected,
as is seen, for example, in the cultivation of rice in
the Malay archipelago and in farther India; in the
state of Polynesian agriculture; in the success at
farming attained by many negroes in Africa. Tropi-
cal soils are by no means all as fertile as is generally
believed. The warm rains throughout the year
leach out the soil, carrying off many salts and
leaving the land poor; the laterite soils which are com-
mon in the tropics are very poor in plant-food
ingredients.
There have thus far been comparatively few native
industries in the tropics, for the reason, doubtless,
that the necessjties of life are readily supplied with-
out the need of manufacture. In the future, with
240
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increasing exploitation by the white race, and under
the control of it, and with growing demands on the
part of the natives themselves, tropical industries are
certain to develop. Yet many tropical natives show
great ingenuity in the use and adaptation of the
simple natural products to which they have access.
Thus the shell of the cocoanut is made into bowls and
other utensils; the cocoanut fibres are plaited into
thatch, baskets, and mats; the cocoanut sterns are
used in the building of houses and boats. Grass
and reeds are plaited, and the bark-cloth of the Pa-
cific islanders and of central Africa is so widely used,
and serves its purposes so well, that it has very prob-
ably kept the natives who use it from advancing to
weaving and spinning. Bamboo and rattan are
widely used for domestic utensils of all sorts; for
hunting and agricultural implements; in construct-
ing houses, boats, rafts, and vehicles for transporta-
tion; in making pipes and musical instruments; and
for other purposes; even for food, rope, and string.
From the tropics man procures many things in ad-
dition to the plant products. For example, the
warm tropical oceans yield him pearls and corals. It
is an interesting fact that, at the present time, Euro-
pean countries, particularly Germany, are devising
and manufacturing machines especially intended for
harvesting and preparing for export the products of
the tropics, such as machines for splitting cocoanüts;
for preparing and extracting oil from the palm fruit;
for making caoutchouc from the sap of the rubber
THE LIFE OF MAN IN THE TROPICS
241
tree, etc. Germany is also devising plans for tropi-
cal cultivators, railroads, and houses.
Special precautions are necessary in packing many
manufactured goods that are to be transported
across the equator, in order to protect them from in-
jury by the dampness. Leather goods, textiles, and
paper are liable to be stained. Arms, cutlery, and all
metal goods need the utmost care to keep them from
rusting. These are best preserved when packed in
cases lined with some absorbent wood well saturated
with hot paraffine wax. It has recently been pointed
out in a Vienna trade journal, that the preservation
of lacquered shoes sent from Europe to Australia
depends upon the circumstance whether they may be
kept moderately cool by the ocean water, low down
in the ship’s hold, or are near the deck, exposed to the
heat. In Indian warehouses woven goods are affected
by the dampness in such a way that they have different
lengths, although all uniformly woven. Even in the
dry month of February, at Bombay, closely woven
imported calicoes, exposed to the air, experience
changes in length from day to day amounting to 8
per cent. Ordinary salt absorbs so much moisture
in the damp latitudes that it has been necessary to
prepare a salt which shall escape this difficulty.
Some Physiological Effects of Tropical Climates.
We are not here concemed with the many complex
questions, physiological and ethnological, which have
arisen in connection with the effects of tropical cli-
mates upon man. There has been much debate con-
16
242
CLIMATE
eenling the effect of the climate upon the colour of
the skin. It was natural that many early writers
should see in the black skin of the negro an effect of
the tropical sun, and should explain the paler colours,
and white, as resultiiig from residence in higher lati-
tudes. It was pointed out, e. g., that among certain
tropical natives the women, who live indoors, are
lighter in colour than the men, who are more ex-
posed. It may be remembered that Darwin, in his
Descent of Man, pointed out that the distribution of
coloured races does not coincide with corresponding
differences of climate, and that no change in colour
has taken place in the Dutch who have lived for sev-
eral generations in south Africa. Darwin also
thought it not an improbable conjecture that the im-
munity of negroes from certain diseases might be
correlated with the colour of their skins, and that this
colour might have been acquired because darker in-
dividuals escaped during successive generations from
these diseases. However opinions may differ con-
cerning the origin of the black skin qf the negro, it is
clear that this colour is an advantage, rather than
otherwise, in helping to cool the body through profuse
perspiration and the resulting evaporation. Black
skin, however it may have been developed, seems to
be well suited to a hot climate. Major Charles E.
Woodruff, of the United States Army, has lately
maintained that the failure of the .white races to col-
onise the tropics.is due to the excess of light which
there prevails, and not to the heat or humidity. He
THE LIFE OF MAN IN THE TROPICS
243
believes that the white man, especially the blond,
gradually becomes disinclined to work on this ac-
count, grows neurasthenie, and finally breaks down.
An effect of climate upon the kind of hair has also
been claimed, but on this point, again, Darwin has
noted that although there are reasons for thinking
that the growth of hair is affected by cold and damp-
ness, he had “ not yet any evidence on this head in
the case of man.” Schlagintweit called attention to
the fact that the inhabitants of Nepal wore much
less head-covering than Europeans, and did not suf-
fer. The sallow, ansemic complexions of white in-
habitants of the tropics are a subject of general
comment.
There are other physiological matters which must
also be passed over without discussion. For example,
it is alleged that a preponderance of females in warm
climates is the effect of the light diet of mothers in
the tropics, whereas a meat diet produces more
males.1 Direct proof of the assertion that sterility
in the white race ensues after three generations in the
tropics is hard to find.
The Equatorial Forests. In the equatorial belt
we find the hot, sultry, cloudy conditions of the
•doldrums, with frequent heavy rains. When the
doldrums migrate north and south, and the trade
winds take their place, there are clearer skies for a
time, and little or no rainfall. There are two rainy
seasons near the equator (equatorial type), and one
1Schenck: Einfluss auf das Geschlechtsverhdltniss, 1898.
244
CLIMATE
rainy season farther away (tropical type). The life
of man in the equatorial belt as a whole is controlled
by the rains. The dense tropical forests of equa-
torial Africa, South America, the Malay peninsula
and archipelago, grow where the rainfall is heaviest.
These forests are dark and depressing; crowded with
creepers and plants of innumerable varieties; rich in
valuable woods such as mahogany, ebony, and rose-
wood; in sap-products such as rubber, and in drugs
such as quinine. Poppig has compared the native
South American tribes with their forest trees. Man
develops rapidly there, as does the vegetation. He
also ages rapidly, like the tree which decays at the
time of its best development. The tropical tree does
not strike its roots firm and deep into the soil; it
spreads them out near the surface, and a high wind
overtums it. So it is, according to Poppig, with the
native. Both he and his trees lack the stability and
endurance of northern forests and of temperate zone
man. There are comparatively few animals in the
dense tropical forests. Reptiles, birds, and mon-
keys are found. The large mammals are in the more
open country.
Such a superabundance of vegetation is unfavour-
able to human occupation. The population is small,
and generally at a very low stage of civilisation, as
illustrated by the Indians of the Amazonian forests
or the Pygmies of the Congo, who wander about with-
out settled homes. The trees and undergrowth act
as a very effective barrier to the advance of civilisa-
THE LIFE ÓF MAN IN THE TROPICS
245
tion from the margins of the forest. The difficulty
and expense of travel and transportation, and of
clearing the forest for purposes of agriculture, oper-
ate to retard the advance of civilised man. The
waves of civilisation, as one writer has put it, beat up
against the forest, but only occasionally break
through it. The northern forests of Argentina,
inhabited by wandering tribes of Indians; the
densely wooded Amazonian provinces of Peru; the
equatorial forests on the west coast of Africa; the
forests of Achin, in northem Sumatra, in the protec-
tion they have afforded the natives in their resistance
against the Dutch; the eastern forested slopes of
Central America, left longest to the native tribes,
while the western, more open, and drier slopes were
first settled by white men and are best developed—
these are all examples of the repelling effects of dense
tropical tree-growth where the advance of civilised
man is concerned. Even the earlier American civil-
isations, the Aztec and the Inca, halted before
forested areas. It has been pointed out that the
Incas were almost as much hemmed in by the forests
on the east as by the Pacific on the west.
In the equatorial forests the men hunt and fish;
collect rubber or other forest products; do a little
planting in the forest clearings, without paying much
attention to the erop when planted. By clearing
away the forest, these people might extend the area
devoted to agriculture, and become farmers. In the
clearings at the margins of the forests there is a eer-
246
CLIMATE
tain amount of agriculture, carried on chiefly by the
women, who are also occupied with domestic duties
while the men are hunting or fighting. Settlements
in these clearings are often abandoned. In the
Malayan forest the natives are graded from those
who are simple nomads to those who have settlements
where they cultivate rice in the wet jungles. Rice
needs much water, and its cultivation in Java is
closely allied with the general question of deforesta-
tion. Where the sago palm grows, and provides
food without the need of much labour, the natives are
least advanced.
Travel through the forest is difficult. Darwin
thought it not unlikely that the habit of carrying
knives for the purpose of cutting down vegetation
contributes much to the frequency of murder among
the tropical peoples. Narrow paths, along which
travellers move in Indian file, are natural ways of
communication unless travel can be by boat, which is
obviously quicker and easier. The natives thus nat-
urally live along the rivers. It has been pointed out
that there is a connection between the method of
carrying goods in the African forests, on the backs or
heads of negro porters, and the slave trade, which
sells the man as well as the goods. Many of the
natives who secure the rubber from the Amazonian
forests, or from those of the Congo, are to-day sub-
jected to hardships which equal those of slavery.
The seasonal floods on many rivers, the Amazon
for example, oblige the natives to build huts on piles
THE LIFE OF MAN IN THE TROPICS
247
to keep them above the water. When the waters rise
higher than the platforms, the people take to their
canoes, until the flood is over. In some places the
floods drive the people to the towns, which are built
on natural eminences. In New Guinea and in the
Mosquito Territory the natives live much in their
boats during the rainy season. In fact, in the former
country so much time is spent on the water that the
people partly lose their ability to walk. They al-
most become amphibious beings. Sir Charles Eliot
reports that some of the native tribes along the
Bahr-el-Gebel, at seasons when mosquitoes are
abundant, use platforms on poles ten or twelve
feet high, as these insects do not fly far above the
ground.
The food supply along the Amazon is dosely re-
lated to the rise and fall of the water. WTien the
river is in flood, the turtles, fish, and aquatic birds
migrate to the northem tributaries, or even to the
Orinoco, where the dry season is on. With the re-
turn of the dry season on the Amazon comes the op-
portunity of the natives to catch the fish and turtles,
and to secure turtles’ eggs. There is thus a very
general seasonal migration among the people. The
flood time is the time of deficiënt food supply. This
explains the origin of the native prayer for a good
dry season. The conditions of life on the Mosquito
Coast are very similar (lat. 10°-15° N.). The
north-east trade there brings the dry season
(spring), when the Indians collect the eggs of alli-
248
CLIMATE
gators and turtles on the dry sand-banks. Living-
stone pointed out that during the great floods in the
inland lake region of Africa the natives live upon,
and cultivate, the large ant hills, in the Bangweolo
and Moëro districts. On the plateau of western
Nyassa, the Ba Bisa profit by the heavy rains in an
interesting way. At such times the hollows are
swampy, so that elephants driven into them become
helpless and are readily killed. Similarly, as reported
by Livingstone, the natives of the islands in the Zam-
bezi River utilise the floods and canoes to hunt buf-
faloes, these animals being easily caught in the wa-
ter. One writer has pointed out that certain African
tribes purposely go naked during the rains, know-
ing that they are thus less likely to becomé chilled.
The great value of the tropical forest products is
leading, and will still further lead, to the settlement
of considerable numbers of whites on the margins of
these forests, and along the rivers which flow through
them. Thus in Brazil, along the lower Amazon and
its tributaries, there are cacao, sugar, coffee, tobacco,
manioc, and rice plantations; in some cases also, sugar
factories, rice and lumber mills. Large cities and
towns thus gradually grow up, like Para and Manaos,
and the native tribes come more and more into con-
tact with civilisation.
Travel and transportation are emphatically con-
trolled by climate throughout the equatorial belt.
Roads become almost or quite impassable during the
rainy season. Lowlands, as in central Africa and in
THE LIFE OF MAN IN THE TROPICS
249
equatorial South America, turn into swamps or tem-
porary lakes, so that all travel may be stopped. In
other places, where boats are used at all seasons, the
•rains give high water and aid, rather than hinder,
travel. The control of the floods of the Chagres
River, on the Isthmus of Panama, is one of the most
difficult problems with which the engineers ' have
dealt. Work on railroads is always much interfered
with difring the rainy season, if not interrupted
altogether. Dense tropical vegetation seriously
obstructs railroad construction and operation. The
roadway is constantly being overgrown, and men
must be kept at work cutting down the weeds, under-
brush, and trees. This involves great expense, and
seriously reduces the earnings of the roads. Recently,
tank-cars which frequently spray the right of way
with a strong poison have come into use, as on
the Guayaquil-Quito line in Ecuador, and on the
Tehuantepec Railroad. Ties and trestles rot quickly,
or are destroyed by insects. Special kinds of ties,
such as Ugnum vitte, or camphor wood, or even iron,
have therefore been used. Although vegetation is
thus a serious handicap to railroads in the moist
tropics, it serves a useful purpose in preventing the
sides of steep cuts from sliding down. The absence
of frost makes possible cuts with steeper sides than in
colder latitudes. Along the older portion of the
Panama Canal, which has been built for some years,
no masonry was needed to keep the banks from cav-
ing in. The heavy vegetation served the purpose of
-
250
CLIMATE
stone and cement. Fevers and other diseases com-
mon in the rainy season of the tropics are also a seri-
ous handicap, and floods and landslides add to the
difficulties. The sultry heat is another obstacle. *
Curious complications in the employment of several
different kinds of labour arose on the Uganda
Railway. For four castes among the Indian work-
men, four separate water-tanks had to be provided,
and if the water in one tank gave out, that particular
one had to be sent by train to be filled, although the
remaining three tanks were full. Dr. H. R. Mill
has pointed out that there are many features on the
Uganda Railway which show climatic control. The
cars are built of metal, in order to defy wood-boring
insects. They have deep ventilators, protected by
wire gauze against mosquitoes. The Windows are of
green glass to give protection against the glare of
the sun.
During the dry season the difflculties are similar to
those noted later under deserts. At that time dust
makes travelling disagreeable, and instead of streams
being impassable, they often dry up, and their beds
serve as roads.
A curious relation of thunder-storms and naviga-
tion is reported by Hann from Maracaibo, Venez-
uela. The lightning flashes from rainy-season
thunder-storms at the south-westem end of the lake
of Maracaibo are used by captains in navigating their
vessels through the strait of Maracaibo. “ El Faro
de Maracaibo,” as these lightnings are locally called,
THE LIFE OF MAN IN THE TROPICS
251
gives a good compass-direction for steering a ship on
dark nights.
The Open Graas Lands of the Tropics: Savannas.
Between the forests on one side and the deserts on the
other comes a transition zone of moderate rainfall.
Here the forests are replaced by an intermediate belt
of more or less open, grassy country, known as the
savanna. There are usually a long dry and a shorter
wet season (summer). Vegetation has but a short
season for growth. Savannas are found in Africa
and in South America both north and south of the
equator. In Africa they include the Sudan; in
South America, the llanos of Venezuela and the cam-
pos of Brazil; in Australia, the downs. The open
Country and the grass cover, which forms natural hay
in the dry season, fit the savannas for grazing pur-
poses. The people are essentially pastoral. Popu-
lation is denser than in the tropical forest, and the
people are more energetic and more advanced. The
African savannas are abundantly supplied with large
animals such as lions, tigers, antelopes, elephants,
rhinoceroses, and giraffes.
Their dependence upon grass and water for their
cattle forces the inhabitants of the savannas to be
more or less nomadic, the more so the more pastoral
the people are. They move their tents and household
goods easily over great distances, stopping where
there are pasturage and water. Their food is supplied
chiefly from their flocks and herds, of cows, goats, or
camels. Agriculture of a somewhat primitive kind
252
CLIMATE
is often combined with grazing in the better-watered
portions of the savannas, the seed being sown at the
beginning of the rains. The population there be-
comes more sedentary. Thus in the Sudan there is
a belt of agriculture nearer the equator, where the
rainfall is heavier, and a pastoral zone farther from
the equator, where there is less rainfall. In these
districts the rainfall varies much from year to year,
and there are frequent droughts and famines.
Thousands of persons may then die of starvation, as
has happened in parts of the Sudan, in Nubia, and
elsewhere within a few years. At such times the
cattle die in large numbers, and where the herds have
been lost by famine or disease it has happened that
certain native tribes (e. g.} the Galla, in eastern
Africa), after suffering terribly from hunger, have
changed their place of residence, turning in part to
plunder and hunting, and in part to farming. A
curious case of seasonal migration into the desert has
been reported of the Tuaregs, who inhabit part of the
region about Lake Chad. The upper class of these
people is nomadic, and during the rainy season re-
tires into the desert with its camels, which do not
like the rains.
All the savannas will in time be more thickly popu-
lated and more valuable than now, owing to the
availability of considerable portions of them for agri-
culture, especially where irrigation can be practised.
Under the supervision of white overseers, the natives
will become better agriculturists and cattle-raisers.
THE LIFE OF MAN IN THE TROPICS
253
In South America, as well as in Australia, the sa-
vannas are in part being sown to wheat. From the
savannas and the neighbouring deserts, ivory, ostrich
feathers, palm oil, dates, gums, and so on, are
secured.
Trade Wind Beits on Land: the Deserts. The
major part of the earth’s surface in the trade wind
beits is a desert, which forms a marked feature of
every rainfall map of the world. These trade wind
deserts, because of their great extent, are of immense
importance from a human standpoint. They are
beits of scanty population. They form great bar-
riers, across which even to-day travel and transporta-
tion are difficult and expensive. The interior of
Africa has been out of contact with the civilised world
largely because of the deserts to the north and south
of it. Goods and passengers go around, rather than
across them. Trails across the desert are easily
effaced by blowing sand, or are shifted as some oasis
dries up. Along their margins, where there is a
moderate rainfall, or where oases, wells, or streams
make permanent settlement possible, the population
is more or less sedentary, agricultural, pastoral, and
commercial, but even here droughts and famines may
occur, and agriculture is not absolutely sure. Riv-
ers which cross the desert gain their water from the
rainier lands beyond, and then flow long distances
without tributaries. The Nile is the classic example
of this. Along such rivers population naturally
gathers; irrigation and agriculture are practised, and
254
CLIMATE
the entire valley becomes an oasis. The Nile and the
rivers of the Coastal desert of South America are
illustrations; in the Deccan, also, the river systems
are the centres of the densest population. It is dif-
ficult to overestimate the effect which the Nile had
upon the civilisation of ancient Egypt. It has been
asserted with good reason that the annual overflow,
by depositing silt and by wiping out the boundaries
of individual tracts of land, obliged the ancient
Egyptians to develop mathematical skill in re-sur-
veying these lands, as it also led to canal and dam
building. Where deserts are irrigated, it is some-
times necessary to guard the water supply, as in Chile
and Peru.
In the desert proper, a nomadic life and a scat-
tered population are characteristic and inevitable re-
sults of the aridity. As Schirmer has expressed it,
“ the purer the desert, the more the inhabitants dis-
perse themselves.” The Saharan nomads camp for
a few months in winter, it may be near the towns,
and then travel with their flocks in summer. The
Bedouins, although they wander to and fro over a
wide area, nevertheless keep within certain recog-
nised limits. In the desert, population gathers
in the oases, as on islands. Here the trails followed
by the caravans come together, like sailing routes at
sea. Thus there is naturally developed a settlement,
in which the people are in places so crowded that
they may be on the verge of starvation all the time.
There are small Arabian towns where the houses are
THE LIFE OF MAX IX THE TROPICS
255
almost crowded on top of one another, producing
something not unlike the modem “ sky-scraper ” of
an American city, where land is scarce and expensive.
When such oases dry up, or are encroached upon by
the desert sands, they are abandoned, and the ruins,
later discovered by some explorer, give the impres-
sion of a diminishing population.
The climate of the trade wind deserts is drier and
more stimulating, and has larger temperature ranges,
than that of the forests and of the savannas. The
need of protection against heat and cold is greater;
food more difficult to obtain; life a harder struggle.
Therefore the desert produces more active, more
energetic, and more Progressive men. They are inde-
pendent, bold, and strong. Nachtigal has pointed
out the difference between the healthy and vigorous
tribes of the Sahara and the less active Sudanese.
The hardy, warlike inhabitants of the desert of Per-
sia and Baluchistan have frequently held in subjec-
tion the people of the richer lowlands on the west.
There is a well recognised difference between the true
nomad desert-dweller and the weaker sedentary.
From the latter, the former often takes tribute, and
if the exactions become unbearable, the unfortunate
sedentary farmer may be forced in self-defence to be-
come a nomad himself. The nomadic life of the des-
ert-dwellers tends to make robbers of them, so that
pillaging of caravans is not an uncommon occurrence.
The utter hopelessness of the isolated Australian
desert seems to have led to a most degraded condition
m
CLIMATE
among its inhabitants. Nearly naked, living on the
lowest forms of desert life, and practising cannibal-
ism and the murder of the weak and helpless, they
have ranked among the lowest human beings in the
world.
The trade wind deserts are gaps in the map of the
world’s civilisation. When the tribes or individu-
als who live along the margins of the deserts are
forced into the deserts, they tend to scatter and dis-
appear. There are also migrations out from the des-
ert into the more fertile regions adjoining, as in the
case of the Tuaregs in the Sudan. The advance of
the nomadic Arabs from the Sahara into the lands of
the more peaceable agricultural negroes to the south
has been compared with the encroachment of the
desert sands over some fertile grass-covered land
along its border,
The more permanent dwellings often have flat
roofs, and are built of stone or adobe, wood and vege-
table products being scarce or entirely lacking. Slop-
ing roofs are not needed, as the protection desired is
not against rain, but against sun and wind. In hot,
dry climates the flat roofs are generally used for
sleeping at night. The houses are low, sometimes
even partly underground, for better protection
against the wind. When the people are on the move
tents are taken, made of skins or, where the materials
are obtainable, of thatch, palm leaves, or grass. The
timber usually comes from the date tree. On the
arid west coast of South America the Incas used
THE LIFE OF MAN IN THE TROPICS
257
adobe bricks chiefly in the regions with least rainfall,
and granite and porphyry on the rainier plateaus.
Even the great Inca temples, built of massive stone
blocks, had light thatched roofs, because but little pro-
tection against rain was necessary. In the Chilean
desert many of the richest mines were discovered in
the early days by men who were hunting for firewood
or tending cattle.
The nights are often cool, and heavier clothing is
wom than by day. Both clothing and food are
simple, and are supplied chiefly from thé flocks and
herds, which are the desert inhabitants’ most precious
possession, or from desert plants, such as the date.
Along the shores of the Persian Gulf, where there is
no wood supply, even boats are made of date leaves,
The dry desert air preserves rather than destroys.
Sun-dried meat may become an article of food, as in
the charq-ui of Peru. Livingstone and others have
noted that the desert peoples of Africa are much less
clean than those who inhabit the moister parts of the
tropics. The lack of water, as well as the belief that
water makes the skin sensitive to the heat, leads to a
great lack of cleanliness. In Abyssinia, Nubia, and
elsewhere, a kind of sand bath is substituted for the
usual bath with water. Protection against dust and
sun is found by covering the head and wearing a veil,
as is done, for example, by the Tuaregs, who are com-
pletely covered with the exception of their eyes.
Some tribes blacken their eyelids and their faces, just
as is done by people in the Himalayas as a protection
«7
258
CLIMATE
against snow-blindness. During dust storms and
high winds all protection may be inadequate» and
death may result.
Utensils of all sorts are made chiefly of leather.
In Nubia, as reported by Speedy, baskets are so
closely woven of leather strips that they are fluid-
proof. As these cannot be placed on the fire, milk
is warmed by dropping red-hot stones into them.
Many desert people become adepts at plaiting and
weaving in leather. Well-digging is an occupation
in which many of the Saharans have by nature been
forced to become skilled. Here and there salt, nitrate,
or borax deposits locally give an exceptional eco-
nomie value to the desert, and furaish employment to
many. Salt may become an important article of ex-
change. The amount of nitrate exported from
Chile is determined largely by the weather and erop
conditions of Europe.
That deserts have had a significant relation to re-
ligious ideas has been suggested by several writers.
Emest Renan points out that the desert is mono-
theistic, its uniformity suggesting a belief in the unity
of God. The desert is conducive to a solitary, medi-
tative life; even to a morbid and fanatical state of
mind. Such conditions, it is believed, fumished good
ground for the growth of such a religion as Moham-
medanism. In his Seas and Skies in Many Lati-
tudes (London, 1888, pp. 42-48), Abercromby
gives two maps, showing respectively the areas of
THE LIFE OF MAN IN THE TROPICS
259
Mohammedanism and the districts in Asia and
Africa with a mean annual rainfall of less than ten
inches. The maps are strikingly similar. The
author adds: “Whether this distribution of a great
creed is the result of chance, or of some deep connec-
tion between the tenets of that religion and climatic
influences, I cannot say;—but still the relation is so
remarkable that I have thought it well to bring the
matter forward.” The rain-ceremonies and rain-
dances among the native tribes of central Australia;
the Indian celebrations of the rise of water in the
Peruvian rivers; the ancient Aztec sacrifices to the
god of rain in Mexico, and other similar customs in
tropical deserts, are natural in a region where water
is of supreme importance. In one of the Australian
rain-ceremonies, the men dance around a mimic water-
hole, imitating the calls and motions of aquatic ani-
mals. These dances are reported as being carefully
timed, by experienced individuals, to come at the
seasons when rain is likely to fall.
The night is cooler and less dusty than the day,
and is the best time for travelling. The camel, which
can go long without food and water, is the natural
beast of burden. Trade is still largely carried on by
means of caravans, which require camels and driv-
ers, and give employment to many men. The con-
struction of railroads across these deserts will present
the same difficulties which have already been met
in the arid regions of the temperate zone. Ties dry
260
CLIMATE
up and twist; the danger from fire is greatly in-
creased, often necessitating fire patrols; fuel is ex-
pensive and must be imported, unless a poor local
fuel, like sheep or llama dung, is used; water for men
and locomotives must be brought in by water-trains,
tank cars, or pipe line, or locally distilled, at consid-
erable expense; cloud-bursts sweep away bridges and
tracks; the number of working hours by day is re-
duced by the heat; drifting sands cover the track and
must constantly be shovelled off; the blowing sand
hinders seeing, and increases friction and wear on the
rolling stock; watchmen to guard against accidents
from blowing sand on the track must be employed;
proper non-dusty ballast is difficult to secure; all
lumber must be brought from moister regions. On
the other hand, the trade wind deserts are, on the
whole, healthy regions. When the Sahara and the
Australian desert are bridged by railroads, and when
the South American Coastal desert is traversed by a
longitudinal line of track from north to south, the
relations of these great arid regions to man will in-
evitably be greatly changed.
Trade Beits at Sea. At sea, the trade wind beits
are closely related to man through their control over
sailing routes, and over voluntary and involuntary
migrations. A glance at any pilot chart will show
that all sailing routes which pass through the trade
wind beits in any ocean are determined by the course
of these winds. The route from Europe to India
furnishes a good example of the advantage that is
THE LIFE OF MAN IN THE TROPICS 261
taken, by mariners of the present day, of the prevail-
ing wind systems of the world. In former times a
vessel was kept close in along the west coast of
Africa, amid calms and adverse winds, and then, after
passing the Cape of Good Hope and leaving Moz-
ambique, she waited for the blowing of the south-west
monsoon, with which she continued her voyage to
India. In 1500, Cabral sailed from the Cape Verde
Islands out into the open sea with the north-east
trades, avoiding the African coast. Keeping farto
westward he discovered Brazil; continued across the
south-east trade, rounded the Cape of Good Hope
with the westerlies, and then proceeded up the east
coast of Africa as had previously been the custom.
In the 17th century the Dutch struck off on the new
route from the Cape of Good Hope, making their
easting in the prevailing westerly winds of the South
Indian Ocean, and then sailing up to India with the
south-east trade. The passage across the equatorial
belt of calms (doldrums), which was formerly much
dreaded, is now so carefully worked out that vessels
may cross where the helt is narrowest, and where
there is therefore the least danger of delay.
Steady winds like the trades certainly tempted the
early navigators to put to sea. The famous voyage
of Columhus, when he discovered America, was fa-
cilitated, if not made possible, by the north-east trade.
The easy outward voyages of the early Spanish
adventurers and colonists took them naturally to that
portion of the Americas where they found climates in
-
262
CLIMATE
which they and their descendant» could live, while to
the Anglo-Saxon originally feil the North American
continent, with its more rigorous climate. The
monsoons of India have, from the earliest days of
trade with the East, been important agents in aiding
commerce. In the Mediterranean, the Etesian winds
—the northward extension of the trade—favoured
early commerce. The migrations of the Malays
to the Melanesian Islands, of the Folynesians,
and of other Pacific islanders, found their occasion
and their possibility in the prevailing winds of those
latitudes. The islands from the Philippines to the
Gilbert Islands are in the north-east trade and from
the Moluccas to the Society Islands in the south-east
trade. Thus intercourse and migrations are easy. In^
the archipelago of the monsoon belt south-east of Asia
trade depends largely upon monsoons. An inter-
esting case is cited by Ratzel, on the authority of von
Maltzan. Two small ports, Bir Ali and Megdaha,
lie opposite one another on the southem coast of
Arabia, in a small bay. The former is protected on
the west, and the latter on the east. Hence the former
is sought by shipping in summer, and the latter in
winter. Both places have grown and really make one
town, the officials and many of the inhabitants mov-
ing twice a year with the seasonal change of wind.
The war expeditions of the native tribes of this
great island region have always been governed by the
monsoons. In many places to-day native boats do
not venture to sea at the height of the monsoon. In
THE LIFE OF MAN IN THE TROPICS 263
the discussions regarding the relative advantages of
the Nicaragua and Panama Canal routes, much em-
phasis was laid upon the prevailing winds in the two
cases. Many of the optimistic predictions concern-
ing the use of the Panama Canal by sailing ves-
sels did not take account of the calms and variable
or adverse winds to be encountered before entering
and on leaving the canal, which necessitate trans-
portation by steamer, or at least some towing of
sailing vessels.
To leeward of the west coast of Africa navigation
is not infrequently interfered with by the so-called
“ tomadoes,” which move westward off the land, and
by dust-storms, which obscure the air and delay
progress.
Tropical cyclones at certain seasons and in certain
parts of the trade wind beits at sea not only damage
shipping, but often devastate towns, bridges, and
crops, bringing starvation, poverty, and not infre-
quently pestilence as well, owing to decaying animal
matter, or fish thrown up by the sea. Thousands
of lives have been lost as the result of such disasters.
The Pacific islands are particularly unfortunate in
this respect. The storm waves produced by these
cyclones are especially severe at the head of the Bay
of Bengal. Native huts are easily blown over by
the cyclonic winds, and it has been pointed out that
the huts elevated on high posts in New Guinea, and
swaying with the wind, fumish good evidence that
the district in which they are found is not visited by
264
CLIMATE
tropical cyclones. In some places, Mauritius, for
example, houses are provided with shutters to be used
in case of a cyclone, and in many places the natives
have resistance to cyclones in mind when they build
their huts. In time, buildings must be erected in the
tropics which will withstand these storms better.
Worcester reports of the Philippines that in order to
save the banana Irees from destruction by typhoons,
some of the natives cut off all the larger leaves when
the approach of a typhoon becomes evident.
Monsoon Districts. Of the monsoon districts on
land, India is the largest example. The two seasons
are strongly contrasted. The success or failure of
the crops depends upon the amount, distribution, and
time of occurrence of the summer monsoon rains.
Famine follows when these rains are deficiënt or un-
favourably distributed, with terrible suffering and
the loss of thousands of lives among men and cattle.
Lately the government of India, at great expense,
has undertaken relief works during times of famine,
including irrigation works. The amount and regu-
larity of the water supply is the (hief factor in deter-
mining the density of population in India.
Travel and transportation in monsoon districts de-
pend closely upon the season. During the rains, the
roads are likely to be bad or impassable, and land-
slides and washouts are common. In the Philippines
the mud is so deep that sledges are used instead of
wheeled vehicles. Communication may be entirely
interrupted by floods. Campaigning under such
THE LIFE OF MAN IN THE TROPICS 265
conditions is extremely difficult, as was abundantly
proved during the American occupation of the
Philippines. Horses, and even water-buffaloes, were
often unahle to haul the guns, one of the difficulties
with the buffaloes being their need of a mud bath in
the hottest part of the day. During the early part of
the American campaign in the Philippines the success
of the American army was achieved in the dry sea-
sons, the natives gaining the upper hand, or at least
making the most progress, during the rains, when
conditions were hardest for the white men.
Native dwellings are adapted to the different sea-
sons, as on the island of Mindoro, where the Mangy-
ans erect simple shelters of rattan and leaves wherever
they happen to be in the dry season, while in the rainy
season the dwellings are more elaborate and more se-
cure. The rain hat and coat of the Filipinos; the
preparations made in north-western Mysore, on the
summit of the western Ghats, in laying in provisions
to last during the long rainy season, as if it were for
an extended voyage at sea; the general use of
punkahs, tatties, grass mats, etc., for cooling pur-
poses during the hot and dry season in India and
Persia, these being often wet, and kept in motion by
coolies; the habit of closing houses during the day
and of staying indoors during the hottest hours,—
. these few cases may suffice to illustrate the con-
trol of climate over the life of man in the monsoon
beits.
Tropical Mountains. Their “ temperate ” climates
266
CLIMATE
have given many tropical mountains and plateaus a
deserved popularity, and the increasing settlement
of the tropics by white men and women will constant-
lv tend to bring such elevations into greater use.
Under these conditions the usual law of the decrease
of population with increase of altitude is locally re-
versed, at least up to a certain height. Mountains
within the polar zones do not increase the habitable
parts of the earth’s surface. Mountains within the
tropics certainly give white men and women a larger
area and more comfortable conditions of habitability.
There is observable a tendency for the altitude of
human settlements to increase from polar latitudes
towards the equator. In the far north man lives close
to sea-level; within and near the tropics there is often
a large population at considerable altitudes, as in the
Himalayas and on the Andean plateaus. In parts of
South America at the present day (e. g., Colombia)
the plateaus are the chief seat of the Spanish and
Spanish-Indian population, and the lowlands are oc-
cupied by the negroes. The talk of removing the Bra-
zilian Capital from Rio de Janeiro to a more elevated
location in the interior province of La Goyaz, and
the govemment offices of the Italian colony of Eritrea
from Massowa, on the Red Sea, to the high plateau
of the Hinterland, shows the upward tendency of
the white man in the tropics. On the other hand,
the production of sugar-cane, coffee, and other valu-
able products will obviously lead more and more to
the development of the lowlands under white control.
THE LIFE OF MAN IN THE TROPICS 267
To the greatest altitudes man is attracted by mineral
wealth, and lives under very hard conditions. Some
of the Tibetans live more or less underground, and
melt ice in order to secure water. High mountains
within the tropics show a vertical succession of cli-
mates from tropical at their base to eternal snow on
their summits. A very striking illustration of this
may he secured by a passenger who travels over the
famous Oroya Railroad, in Peru. This road runs
from sea-level to a height of 15,665 feet, and then de-
scends again to about 12,000 feet. The first part of
the journey is through fields of sugar-cane and cot-
ton; at about 5000 feet a zone of fruit trees is passed
through; at 10,500 feet there is a district famous for
its potatoes, where little else is grown; above this, the
altitude is so great as to preclude the growth of any-
thing but grass. At the highest point reached, the
snow lies on the mountain summits throughout the
year, and the traveller may enjoy a snowstorm in the
middle of summer (December-February). In the
interior valley, farm produce is again seen growing.
This whole succession of climates may be passed
through in the short space of ten hours. Tropical
mountains may thus produce temperate zone crops.
In the deserts, mountains may be covered with for-
ests and other vegetation, by reason of the rainfall
which they provoke. Here man naturally settles,
finding water and perhaps favourable conditions for
agriculture. Such mountains become “ islands ” of
denser population, as do the streams which run out
268
CLIMATE
from them to wither away in the desert. In Dar
Fur, in the eastern Sudan, most of the inhabitants
live in or near, and in close dependence upon,
the Marra Mountains. Kilimanjaro, in equatorial
Africa, rises as an island above the surrounding
steppes, and is in the centre of a large population.
At the southem foot of the Atlas Mountains there
are three ethnological zones, from the nomadic desert-
dwelling Tuareg to the Berber tribes scattered in the
mountains, with a denser population in the strip of
oasis between.
Thè permanent physiological effects of tropical
mountain climates have not as yet been carefully
studied. Junghuhn has noted an improvement in
the physical condition of people who live at altitudes
of 6000 to 6500 feet in Java; in Africa, the Zulus and
Hovas have been instanced as fumishing an example
of the strengthening influence of mountain climates,
and other cases are cited of mountain tribes who rob,
or rule over, lowland tribes. On the other hand, in
Mexico, Jourdanet has described the anemie condi-
tion, poor physical development, low birth-rate, and
short lives of the inhabitants of the plateau of Ana-
huac, and Chamay noted the fact that the Indians
who brought sulphur from Popocatepetl feil off in
bodily vigour at an early age. Prescott, however, in
his Conquest of Mexico, noted that the physical
development of the Tlascalans on the plateau was bet-
ter than that of the people of the lowlands. The en-
larged lung-capacity of the inhabitants of the lofty
TEE LIFE OF MAN IN THE TROPICS 269
punas on the west coast of South America has natu-
rally been attributed to the effect of the rarefied at-
mosphere. It is interesting to observe that it often
happens that plateau and mountain peoples sicken
and are unable to work when taken to sea-level, and
the same thing is true of lowlanders who are taken
to considerable altitudes. The Aymara Indians of
Peru, when taken down to sea-level by the Spaniards,
could not stand the change. Great difficulty has
been found, as pointed out by Spence, in securing
labourers on coffee plantations at altitudes of 4000
to 6000 feet in South America. Labourers from
greater altitudes and from near sea-level alike become
ill and unfit for work. Additional examples might be
cited.
Special mention may be made here of a peculiar
relation between climate and man on certain lofty
tropical mountains, which are snow-capped, and
which fumish a supply of snow or ice for refrigerat-
ing purposes in the towns below them. Thus in
Ecuador, snow is carried to Quito from the upper
slopes of Pichincha; to Riobamba and Ambato from
the slopes qf Chimborazo. Ambato used to supply
its brewery with snow from the same mountain.
Guayaquil was formerly supplied with ice in the same
way. In Colombia, Popayan, in the department of
Cauca, is also supplied with ice and snow from
neighbouring mountains. In parts of Syria, also,
snow, gathered in the mountains, is packed firmly
in pits dug in the ground, and covered with straw
270
CLIMATE
and leaves. It is later sold. In Mexico, snow is
carried from the summit of Colima to the towns on
the hot plains below. Howarth notes the discovery
of an “ ice factory ” in one of the highest valleys in
Oajaca, in Mexico, at an altitude of 8000-9000 feet.
In this case the active nocturnal cooling by radiation
is the effective climatic factor at work. “ The
ground was covered with a vast number of shallow
wooden troughs, which are filled at nightfall with
water from the dividing stream, and during the nights
of the winter months this becomes covered with a film
of ice not more than one-eighth of an inch thick. In
the moming this is removed and shovelled into holes
in the ground, and covered up with earth, after which
it consolidates and is cut out in blocks and sent down
by mules, where there seems to be a ready market at
all seasons.” On the high veldt the Boers keep their
provisions by letting them cool outdoors at night.
The peculiarly dry climate of the plateaus of the west
coast of South America is due to the leeward posi-
tion, west of the Cordilleras. The Incas preserved
their dead by allowing them to mummify naturally
in the dry, rare atmosphere.
The construction of railroads at high altitudes in
the tropics, as on the west coast of South America,
has been delayed and rendered expensive by moun-
tain sickness, and by man’s decreased efficiency for
work; by cloud-bursts, flooded rivers, and landslides.
In the higher passes over the mountains, diurnal
winds are sometimes met with of such velocity that
THE LIFE OF MAN IN THE TROPICB 271
travelling by day is impossible at certain seasons.
Moritz Wagner has described the down-cast winds
from the snowfields near Quito, which at certain
times are of such violence as entirely to interrupt
travel across the Chimborazo passes. Darwin and
many others have noted the diurnal variation in the
height of water in rivers fed by melting snow. Such
streams are easiest to ford in the early moming,
when the water is lowest.
CHAPTER IX
THE LIFE OF MAN IN THE TEMPERATE ZONES
Climate and Man in the Temperate Zones: General—Northward
Movement of Civilisation in the North Temperate Zone—
Present-day Migrations within the Temperate Zones—The
Continents and the Temperate Zones—Differences between
Northerners and Southemers—Variety of Conditions in the
Temperate Zones: Classification—Life of Man in the Forests
of the Temperate Zones—Forest Clearings—The Steppes—
Climates and Crops in the Temperate Zones—The Des-
erts—Mountains—Climate and Weather: Some Mental Effects
—Climate and Weather and Military Operations—Railroads—
Transportation by Water—Various Effects of the Weather*
Climate and Man in the Temperate Zones: Gen-
eral. Intermediate in location, in mean temperature,
and in their physiological effects, the temperate
zones, whatever was the condition in the past, are to-
day clearly the centre of the world’s civilisation, as
they have also been the scenes of the most important
historical developments for several centuries. From
the temperate zones have come the explorers and ad-
venturers of the past, and are coming the exploiters
and colonisers of to-day. In the occurrence of the
temperate zone seasons lies much of the secret—who
can say how much of it?—of the energy, ambition,
272
LIFE OF MAN IN TEMPERATE ZONES 273
self-reliance, industry, thrift, of the inhabitant of the
temperate zones. Guyot did not exaggerate when
he wrote:
Li the temperate zones all is activity, movement. The
alternations of heat and cold, the changes of the sea-
sons, a fresher and more bracing air, incite man to a
constant struggle, to forethought, to the vigorous employ-
ment of all his faculties. A more economical Nature yields
nothing except to the sweat of his brow; every gift on her
part is a recompense for effort on his. . . . Invited to
labour by everything around him, he soon finds, in the exer-
cise of all his faculties, at once progress and well-being.
The monotonous heat of the tropics and the con-
tinued cold of the polar zones are both depressing.
Their tendency is to operate against man’s highest
development. The seasonal changes of the temper-
ate zones stimulate man to activity. They develop
him physically and mentally. They encourage higher
civilisation. A cold, stormy winter necessitates fore-
thought in the preparation of clothing, food, and
shelter during the summer. Carefully planned,
steady, hard labour is the price of living in these
zones. Development must result from such condi-
tions. In the warm, moist tropics, life is too easy.
In the cold polar zones it is too hard. Temperate
zone man can bring in what he desires of polar and
tropical products, and himself raises what he needs
in the great variety of climates of the intermediate
latitudes. Near the poles the growing season is too
short. In the moist tropics it is so long that there is
-
262
CLIMATE
which they and their descendant» could live, while to
the Anglo-Saxon originally feil the North American
continent, with its more rigorous climate. The
monsoons of India have, from the earliest days of
trade with the East, been important agents in aiding
commerce. In the Mediterranean, the Etesian winds
—the northward extension of the trade—favoured
early commerce. The migrations of the Malays
to the Melanesian Islands, of the Folynesians,
and of other Pacific islanders, found their occasion
and their possibility in the prevailing winds of those
latitudes. The islands from the Philippines to the
Gilbert Islands are in the north-east trade and from
the Moluccas to the Society Islands in the south-east
trade. Thus intercourse and migrations are easy. In^
the archipelago of the monsoon belt south-east of Asia
trade depends largely upon monsoons. An inter-
esting case is cited by Ratzel, on the authority of von
Maltzan. Two small ports, Bir Ali and Megdaha,
lie opposite one another on the southem coast of
Arabia, in a small bay. The former is protected on
the west, and the latter on the east. Hence the former
is sought by shipping in summer, and the latter in
winter. Both places have grown and really make one
town, the officials and many of the inhabitants mov-
ing twice a year with the seasonal change of wind.
The war expeditions of the native tribes of this
great island region have always been governed by the
monsoons. In many places to-day native boats do
not venture to sea at the height of the monsoon. In
THE LIFE OF MAN IN THE TROPICS 263
the discussions regarding the relative advantages of
the Nicaragua and Panama Canal routes, much em-
phasis was laid upon the prevailing winds in the two
cases. Many of the optimistic predictions concern-
ing the use of the Panama Canal by sailing ves-
sels did not take account of the calms and variable
or adverse winds to be encountered before entering
and on leaving the canal, which necessitate trans-
portation by steamer, or at least some towing of
sailing vessels.
To leeward of the west coast of Africa navigation
is not infrequently interfered with by the so-called
“ tomadoes,” which move westward off the land, and
by dust-storms, which obscure the air and delay
progress.
Tropical cyclones at certain seasons and in certain
parts of the trade wind beits at sea not only damage
shipping, but often devastate towns, bridges, and
crops, bringing starvation, poverty, and not infre-
quently pestilence as well, owing to decaying animal
matter, or fish thrown up by the sea. Thousands
of lives have been lost as the result of such disasters.
The Pacific islands are particularly unfortunate in
this respect. The storm waves produced by these
cyclones are especially severe at the head of the Bay
of Bengal. Native huts are easily blown over by
the cyclonic winds, and it has been pointed out that
the huts elevated on high posts in New Guinea, and
swaying with the wind, fumish good evidence that
the district in which they are found is not visited by
264
CLIMATE
tropical cyclones. In some places, Mauritius, for
example, houses are provided with shutters to be used
in case of a cyclone, and in many places the natives
have resistance to cyclones in mind when they build
their huts. In time, buildings must be erected in the
tropics which will withstand these storms better.
Worcester reports of the Philippines that in order to
save the banana Irees from destruction by typhoons,
some of the natives cut off all the larger leaves when
the approach of a typhoon becomes evident.
Monsoon Districts. Of the monsoon districts on
land, India is the largest example. The two seasons
are strongly contrasted. The success or failure of
the crops depends upon the amount, distribution, and
time of occurrence of the summer monsoon rains.
Famine follows when these rains are deficiënt or un-
favourably distributed, with terrible suffering and
the loss of thousands of lives among men and cattle.
Lately the government of India, at great expense,
has undertaken relief works during times of famine,
including irrigation works. The amount and regu-
larity of the water supply is the (hief factor in deter-
mining the density of population in India.
Travel and transportation in monsoon districts de-
pend closely upon the season. During the rains, the
roads are likely to be bad or impassable, and land-
slides and washouts are common. In the Philippines
the mud is so deep that sledges are used instead of
wheeled vehicles. Communication may be entirely
interrupted by floods. Campaigning under such
THE LIFE OF MAN IN THE TROPICS 265
conditions is extremely difficult, as was abundantly
proved during the American occupation of the
Philippines. Horses, and even water-buffaloes, were
often unahle to haul the guns, one of the difficulties
with the buffaloes being their need of a mud bath in
the hottest part of the day. During the early part of
the American campaign in the Philippines the success
of the American army was achieved in the dry sea-
sons, the natives gaining the upper hand, or at least
making the most progress, during the rains, when
conditions were hardest for the white men.
Native dwellings are adapted to the different sea-
sons, as on the island of Mindoro, where the Mangy-
ans erect simple shelters of rattan and leaves wherever
they happen to be in the dry season, while in the rainy
season the dwellings are more elaborate and more se-
cure. The rain hat and coat of the Filipinos; the
preparations made in north-western Mysore, on the
summit of the western Ghats, in laying in provisions
to last during the long rainy season, as if it were for
an extended voyage at sea; the general use of
punkahs, tatties, grass mats, etc., for cooling pur-
poses during the hot and dry season in India and
Persia, these being often wet, and kept in motion by
coolies; the habit of closing houses during the day
and of staying indoors during the hottest hours,—
. these few cases may suffice to illustrate the con-
trol of climate over the life of man in the monsoon
beits.
Tropical Mountains. Their “ temperate ” climates
266
CLIMATE
have given many tropical mountains and plateaus a
deserved popularity, and the increasing settlement
of the tropics by white men and women will constant-
lv tend to bring such elevations into greater use.
Under these conditions the usual law of the decrease
of population with increase of altitude is locally re-
versed, at least up to a certain height. Mountains
within the polar zones do not increase the habitable
parts of the earth’s surface. Mountains within the
tropics certainly give white men and women a larger
area and more comfortable conditions of habitability.
There is observable a tendency for the altitude of
human settlements to increase from polar latitudes
towards the equator. In the far north man lives close
to sea-level; within and near the tropics there is often
a large population at considerable altitudes, as in the
Himalayas and on the Andean plateaus. In parts of
South America at the present day (e. g., Colombia)
the plateaus are the chief seat of the Spanish and
Spanish-Indian population, and the lowlands are oc-
cupied by the negroes. The talk of removing the Bra-
zilian Capital from Rio de Janeiro to a more elevated
location in the interior province of La Goyaz, and
the govemment offices of the Italian colony of Eritrea
from Massowa, on the Red Sea, to the high plateau
of the Hinterland, shows the upward tendency of
the white man in the tropics. On the other hand,
the production of sugar-cane, coffee, and other valu-
able products will obviously lead more and more to
the development of the lowlands under white control.
THE LIFE OF MAN IN THE TROPICS 267
To the greatest altitudes man is attracted by mineral
wealth, and lives under very hard conditions. Some
of the Tibetans live more or less underground, and
melt ice in order to secure water. High mountains
within the tropics show a vertical succession of cli-
mates from tropical at their base to eternal snow on
their summits. A very striking illustration of this
may he secured by a passenger who travels over the
famous Oroya Railroad, in Peru. This road runs
from sea-level to a height of 15,665 feet, and then de-
scends again to about 12,000 feet. The first part of
the journey is through fields of sugar-cane and cot-
ton; at about 5000 feet a zone of fruit trees is passed
through; at 10,500 feet there is a district famous for
its potatoes, where little else is grown; above this, the
altitude is so great as to preclude the growth of any-
thing but grass. At the highest point reached, the
snow lies on the mountain summits throughout the
year, and the traveller may enjoy a snowstorm in the
middle of summer (December-February). In the
interior valley, farm produce is again seen growing.
This whole succession of climates may be passed
through in the short space of ten hours. Tropical
mountains may thus produce temperate zone crops.
In the deserts, mountains may be covered with for-
ests and other vegetation, by reason of the rainfall
which they provoke. Here man naturally settles,
finding water and perhaps favourable conditions for
agriculture. Such mountains become “ islands ” of
denser population, as do the streams which run out
268
CLIMATE
from them to wither away in the desert. In Dar
Fur, in the eastern Sudan, most of the inhabitants
live in or near, and in close dependence upon,
the Marra Mountains. Kilimanjaro, in equatorial
Africa, rises as an island above the surrounding
steppes, and is in the centre of a large population.
At the southem foot of the Atlas Mountains there
are three ethnological zones, from the nomadic desert-
dwelling Tuareg to the Berber tribes scattered in the
mountains, with a denser population in the strip of
oasis between.
Thè permanent physiological effects of tropical
mountain climates have not as yet been carefully
studied. Junghuhn has noted an improvement in
the physical condition of people who live at altitudes
of 6000 to 6500 feet in Java; in Africa, the Zulus and
Hovas have been instanced as fumishing an example
of the strengthening influence of mountain climates,
and other cases are cited of mountain tribes who rob,
or rule over, lowland tribes. On the other hand, in
Mexico, Jourdanet has described the anemie condi-
tion, poor physical development, low birth-rate, and
short lives of the inhabitants of the plateau of Ana-
huac, and Chamay noted the fact that the Indians
who brought sulphur from Popocatepetl feil off in
bodily vigour at an early age. Prescott, however, in
his Conquest of Mexico, noted that the physical
development of the Tlascalans on the plateau was bet-
ter than that of the people of the lowlands. The en-
larged lung-capacity of the inhabitants of the lofty
TEE LIFE OF MAN IN THE TROPICS 269
punas on the west coast of South America has natu-
rally been attributed to the effect of the rarefied at-
mosphere. It is interesting to observe that it often
happens that plateau and mountain peoples sicken
and are unable to work when taken to sea-level, and
the same thing is true of lowlanders who are taken
to considerable altitudes. The Aymara Indians of
Peru, when taken down to sea-level by the Spaniards,
could not stand the change. Great difficulty has
been found, as pointed out by Spence, in securing
labourers on coffee plantations at altitudes of 4000
to 6000 feet in South America. Labourers from
greater altitudes and from near sea-level alike become
ill and unfit for work. Additional examples might be
cited.
Special mention may be made here of a peculiar
relation between climate and man on certain lofty
tropical mountains, which are snow-capped, and
which fumish a supply of snow or ice for refrigerat-
ing purposes in the towns below them. Thus in
Ecuador, snow is carried to Quito from the upper
slopes of Pichincha; to Riobamba and Ambato from
the slopes qf Chimborazo. Ambato used to supply
its brewery with snow from the same mountain.
Guayaquil was formerly supplied with ice in the same
way. In Colombia, Popayan, in the department of
Cauca, is also supplied with ice and snow from
neighbouring mountains. In parts of Syria, also,
snow, gathered in the mountains, is packed firmly
in pits dug in the ground, and covered with straw
270
CLIMATE
and leaves. It is later sold. In Mexico, snow is
carried from the summit of Colima to the towns on
the hot plains below. Howarth notes the discovery
of an “ ice factory ” in one of the highest valleys in
Oajaca, in Mexico, at an altitude of 8000-9000 feet.
In this case the active nocturnal cooling by radiation
is the effective climatic factor at work. “ The
ground was covered with a vast number of shallow
wooden troughs, which are filled at nightfall with
water from the dividing stream, and during the nights
of the winter months this becomes covered with a film
of ice not more than one-eighth of an inch thick. In
the moming this is removed and shovelled into holes
in the ground, and covered up with earth, after which
it consolidates and is cut out in blocks and sent down
by mules, where there seems to be a ready market at
all seasons.” On the high veldt the Boers keep their
provisions by letting them cool outdoors at night.
The peculiarly dry climate of the plateaus of the west
coast of South America is due to the leeward posi-
tion, west of the Cordilleras. The Incas preserved
their dead by allowing them to mummify naturally
in the dry, rare atmosphere.
The construction of railroads at high altitudes in
the tropics, as on the west coast of South America,
has been delayed and rendered expensive by moun-
tain sickness, and by man’s decreased efficiency for
work; by cloud-bursts, flooded rivers, and landslides.
In the higher passes over the mountains, diurnal
winds are sometimes met with of such velocity that
THE LIFE OF MAN IN THE TROPICB 271
travelling by day is impossible at certain seasons.
Moritz Wagner has described the down-cast winds
from the snowfields near Quito, which at certain
times are of such violence as entirely to interrupt
travel across the Chimborazo passes. Darwin and
many others have noted the diurnal variation in the
height of water in rivers fed by melting snow. Such
streams are easiest to ford in the early moming,
when the water is lowest.
CHAPTER IX
THE LIFE OF MAN IN THE TEMPERATE ZONES
Climate and Man in the Temperate Zones: General—Northward
Movement of Civilisation in the North Temperate Zone—
Present-day Migrations within the Temperate Zones—The
Continents and the Temperate Zones—Differences between
Northerners and Southemers—Variety of Conditions in the
Temperate Zones: Classification—Life of Man in the Forests
of the Temperate Zones—Forest Clearings—The Steppes—
Climates and Crops in the Temperate Zones—The Des-
erts—Mountains—Climate and Weather: Some Mental Effects
—Climate and Weather and Military Operations—Railroads—
Transportation by Water—Various Effects of the Weather*
Climate and Man in the Temperate Zones: Gen-
eral. Intermediate in location, in mean temperature,
and in their physiological effects, the temperate
zones, whatever was the condition in the past, are to-
day clearly the centre of the world’s civilisation, as
they have also been the scenes of the most important
historical developments for several centuries. From
the temperate zones have come the explorers and ad-
venturers of the past, and are coming the exploiters
and colonisers of to-day. In the occurrence of the
temperate zone seasons lies much of the secret—who
can say how much of it?—of the energy, ambition,
272
LIFE OF MAN IN TEMPERATE ZONES 273
self-reliance, industry, thrift, of the inhabitant of the
temperate zones. Guyot did not exaggerate when
he wrote:
Li the temperate zones all is activity, movement. The
alternations of heat and cold, the changes of the sea-
sons, a fresher and more bracing air, incite man to a
constant struggle, to forethought, to the vigorous employ-
ment of all his faculties. A more economical Nature yields
nothing except to the sweat of his brow; every gift on her
part is a recompense for effort on his. . . . Invited to
labour by everything around him, he soon finds, in the exer-
cise of all his faculties, at once progress and well-being.
The monotonous heat of the tropics and the con-
tinued cold of the polar zones are both depressing.
Their tendency is to operate against man’s highest
development. The seasonal changes of the temper-
ate zones stimulate man to activity. They develop
him physically and mentally. They encourage higher
civilisation. A cold, stormy winter necessitates fore-
thought in the preparation of clothing, food, and
shelter during the summer. Carefully planned,
steady, hard labour is the price of living in these
zones. Development must result from such condi-
tions. In the warm, moist tropics, life is too easy.
In the cold polar zones it is too hard. Temperate
zone man can bring in what he desires of polar and
tropical products, and himself raises what he needs
in the great variety of climates of the intermediate
latitudes. Near the poles the growing season is too
short. In the moist tropics it is so long that there is
-
274
CLIMATE
little inducement to labour at any special time. The
regularity and the. need of outdoor work during a
part of the year are important factors in the develop-
ment of man in the temperate zones. Where work is
a universal necessity, labour becomes dignified, well-
paid, intelligent, independent.
Behind our civilisation there lies what has been well
called a “climatic discipline,”—the discipline of a
cool season which shall refresh and stimulate, both
physically and mentally, and prevent the deadening
effect of continued heat. On the other hand, a very
long winter is about as unfavourable as a very long
summer. If outdoor work is seriously interrupted,
progress is retarded. Buckle based certain too broad
generalisations on this consideration, and saw in it
an explanation of similar national characteristics
among peoples whose outdoor work is interrupted for
the same length of time. But it is clear that the
length of the farming season is a large factor in con-
trolling the return from the soil, the kind of work
done, and the manner of doing it. It is not sur-
prising to leam that the difficulty of keeping farm
labourers through the long winter has in the past been
a handicap in western Canada, and that it was urged
against the abolition of slavery in Russia that it would
be impossible, without some form of compulsion, to
keep farm-hands through the winter.
Northward Movement of Civilisation in the North
Temperate Zone. The gradual migration of the
centre of civilisation away from the tropics, and the
LIFE OF MAN IN TEMPERATE ZONES 275
highest development of the human race, not where
life is easiest, but in extra-tropical latitudes, are
significant.
“ Slowly but surely,” as Benjamin Kidd says [Control of
the Tropic», 51-52], “ we see the seat of empire and au-
thority moving like the advancing tide northward. The
evolution of character which the race has undergone has
been northwards from the tropics. . . . Underneath all the
outward national quarrels of Europe there has been going
on for centuries what is really a struggle between what we
might call the Latin type of civilisation, represented by the
Southern races, and that type of civilisation which has been
developed in northem Europe.”
From the Mediterranean region, where the world’s
civilisation, its commerce, and its power were long
centred, westward through Spain and Portugal, the
migration continued farther and farther north in
Europe, until Holland and then England became the
dominant power. From lands of more genial cli-
mates to lands of colder and longer winters, but also
of the most active and energetic races, the migration
has taken place. The advance of Christianity, from
its origin in the subtropical belt of Eurasia into higher
latitudes, has been pointed to as another illustration
of the same tendency. Together with this northward
tendency of civilisation there has run through the past
an equatorward movement, already noted in the case
of the tropics, of the stronger peoples of the north
toward the milder and more genial Southern latitudes,
involving historical events of great importance.
276
CLIMATE
Present-day Migrations within the Temperate
Zones. Within the north temperate zone especially,
and also across from the north to the south temper-
ate, vast, peaceful migrations are taking place, deter-
mined largely by climatic considerations. From
Europe and Asia to the United States alone, a million
people a year are now migrating. These immigrants
have shown marked tendencies to settle where cli-
mate, soil, and occupations are most like those of their
old homes, although the fact that most of them land
at one port on the eastern seaboard, the concentra-
tion of industries in certain sections, and other Con-
trols, have operated very effectively to counteract
and interfere with this tendency. Scandinavians,
for example, have gone largely into the north-west;
and in the future the southem parts of the United
States will doubtless have a large Latin popula-
tion, chiefly of Italians and Spaniards, who will there
find homes and occupations in climates best suited to
their needs. Canada has grown slowly, partly on ac-
count of the repelling effect of her long, cold winters
and her generally severe climate. Of late years,
however, the rapid settlement of farming lands in the
United States, the attraction of free, or cheap, lands
in western Canada, and the success which has been at-
tained in raising wheat and other crops during the
short but favourable Canadian summer, have com-
bined to induce a considerably increased immigration
of farmers from the United States, and of Europeans,
into Canada. This migration within the temperate
LIFE OF MAN IN TEMPERATE ZONES 277
zone is peopling Canada, South Africa, and Aus-
tralia with the same stock that occupies the home-
land of the British Isles. Therefore institutions and
govemment essentially similar to those at home are
possible in these colonies of England beyond the sea.
The case is very different in tropical climates, as has
been seen. Russia will later be found to gain great
strength from the fact that she has expanded east-
ward within the same zone.
In Argentina, the climatic control of migrations is
even more clearly marked than in the United States,
the Italians tending to settle towards the north, where
the climate is most like their own, while the races
from northern Europe show a tendency towards the
south.
It is interesting to observe how immediately con-
trolled by the special weather conditions of even one
season these voluntary migrations may be. Years of
sufficiënt rainfall and abundant crops in the United
States are always followed by a larger immigration.
A failure of crops in Europe, whether it be of wheat
in one country, or of fruit in another, or of potatoes in
another, resulting from drought, or storms, or exces-
sive rainfall, always promotes a larger exodus from
the country concerned. There is, furthermore, a
considerable seasonal migration across the Atlantic.
Thousands of Italians come to the United States in
the spring to work during the warmer months, when
farm and outdoor labourers are in demand, and re-
turn to the milder climate of Italy for the winter.
278
CLIMATE
Similarly there is a seasonal migration, also chiefly of
Italians, to Argentina at harvest time. The possible
effects of the advancing ice-sheet of the glacial period
in producing forced migrations equatorward may be
mentioned, in passing, as another example of climatic
Controls over human movements.
There is also an interesting tendency westward,
observable not only in the westward “ course of em-
pire,” but in the advantages enjoyed, in the belt of
prevailing westerly winds, by those who live in the
western quarters of cities. The “ west ends ” are
usually the most fashionable and the newest sections
of these cities, while the quarters to leeward, the
“ east sides ” and “ east ends,” are inhabited by the
poorer classes. Ratzel points out that among
the Arabs of Syria the tent farthest west is that of
the sheik.
The Continent8 and the Temperate Zone. Europe
is well situated climatically, being almost altogether
in the temperate zone, and open to the ocean on the
west, so that nearly all parts of it are well watered.
Asia is an overgrown continent. Much of it is in
the temperate zone, it is true, but the interior is so
far from the sea that the climate is severe and the
rainfall very deficiënt. This condition of hopeless
aridity is depressing, in the extreme, and this region
is prevented from becoming thickly populated or im-
portant on that account.
Most of Africa is within the tropics. lts plateaus
will furnish considerable areas not wholly unfavour-
LIFE OF MAN IN TEMPERATE ZONES 279
able for white settlement. The southem part of
Africa is just within the marginal sub-tropical belt
of the south temperate zone. The same is true of
Australia.
North America is widest in the temperate zone,
which is one of its greatest assets. It suffers from the
extreme cold of its winters in the north, and from the
rain-shadow effect of its western mountains, which
gives the interior basin and part of the western plains
deficiënt precipitation.
South America is widest within the tropics. lts
west coast is peculiar in having the tempering in-
fluence of high plateaus in the interior and of a cool
ocean current along the coast. Its southem portion
tapers off into the south temperate zone. This part
of South America, and the sc&ttering islands of the
ocean area in these latitudes, suffer from an equable
but cheerless, depressing, and inhospitable climate.
The forlorn natives of Tierra del Fuego, most inade-
quately clothed and housed; living on shell-fish and
other sea-food; with the poorest kind of utensils and
implements; nomadic in habits; shifting their single
fur garment from side to side according to the wind
direction—these fumish a good illustration of man’s
mastery by a climate which Darwin described in the
following words: “ It would be diflicult to imagine a
scene where he (man) seemed to have fewer claims or
less authority. The inanimate works of nature—
rock, ice, snow, wind, water—all warring with each
other, yet combined against man—here reigned in
280
CLIMATE
absolute sovereignty.” The Falkland Islands, by
reason of their dull, moist, cool, and windy climate,
produce nothing but a few poor potatoes and some
berries. All other food, excepting mutton and beef,
has to be imported. Very different is the life of man
in the same latitudes of the continents in the northem
hemisphere, where a more severe climate has given
better opportunity for man’s development.
Differences between Northerners and Southemers.
There are certain broad, distinguishing charac-
teristics of man in the temperate and tropical zones,
in determining which it is reasonable to believe
that climate has played a part. Similarly, there
has been a natural tendency to attribute certain
differences between northerners and southerners in
the temperate zones to a difference in climate.
There is an opinion that the former, living in
a duller, harsher climate, with long and dreary
winters, are more serious, more industrious, more
enterprising, and act after more mature delibera-
tion, than the latter who, reflecting their brighter
skies, are more cheérful, more emotional, more
impulsive, more genial, more generous, but also
less energetic, and more easy-going. It has recently
been pointed out by Professor Jerome Dowd that
labour organisations in the southem United States
are hampered by their liability to hasty, ill-advised
action. The northemer must exercise more fore-
thought, care, industry, and prudence; he has to work
harder, and is usually better paid than the southemer.
LIFE OF MAN IN TEMPERATE ZONES 281
These national differences are proverbial between
northem and Southern Germans, French, Spanish,
Russians, Italians, Arabs, and other peoples. The
influence of climate has likewise been traced in the
sad, even pessimistic tone of much of the northern
literature, and in the gravity and melancholy of mod-
ern northem music, as well as of the older northem
folk-songs.
The question is a very complex one, often much
complicated by actual racial differences between the
northem and southem people of the same country.
Yet even racial distinctions are more or less directly
traceable, in many instances, to climate. Thus a re-
cent writer, Gustave Michaud (The Century, March,
1908), has told us that the Baltic race
is probably the result of the natural selection by a cold
climate over emigrants who belonged to the primitive Medi-
terranean race, and who gradually moved northward. Many
of their mental as well as their physical characteristics find
an ezplanation in that hypothesis; those individuals who,
through lack of ingenuity, foresight, or activity, were un-
able to meet the rcquirements of 'a severe winter, perished
generation after generation; their posterity was constantly
decreased, and the posterity of the active, energetic, and
thoughtful was thereby relatively increased.
Sir Archibald Geikie, in his Scottieh Reminiscences,
has emphasised the climatic influence in producing
the grim character of the Scot in the following
words: “ The gloom of his valleys is deepened by the
canopy of cloud which for so large a portion of the
282
CLIMATE
year rests upon the mountain ridges and cuts off
the light and heat of the sun. Hence his harvests
are often thrown into the late autumn, and in many
a season his thin and scanty crops rot on the ground,
leaving him face to face with starvation and an in-
clement winter. Under these adverse circumstances
he could hardly fail to become more or less subdued
and grim.”
Draper emphasised the important historical con-
sequences of the difference in the characteristics of
northerners and southemers in the United States,
which he attributed largely to climate, and which
found expression in the Civil War. The climate
of Virginia, somewhat more genial than that of New
England, may not unreasonably be supposed to have
made its mark upon the early settlers in the former
state, while the Puritans were struggling against the
harsher forces of nature in the north-east. The
Boers in Africa have developed along lines different
from those of the Dutch in the United States. The
climate, soil, and crops of the Southern States made
negro labour highly desirable, even necessary, and
the presence of the negro invölved some form of com-
pulsion—slavery.
Variety of Conditions in the Temperate Zones:
Classification. The temperate zones embrace so great
a variety of climates that it is not practicable to con-
sider the relations of climate and man according to
any rigid climatic scheme. It is simpler, as well as
more logical, to consider the typical examples here
LIFE OF MAN IN TEMPERATE ZONES 283
selected according to the broad classification of for-
ests, steppes, and deserts. This is essentially a scheme
which depends upon rainfall, and is, therefore, a
reasonable one for adoption by those who approach
the subject from a climatic standpoint.
Life of Man in the Forest8 of the Temperate
Zones. The forests of the temperate zones are
chiefly coniferous on highlands and in colder climates,
and deciduous on lowlands and in lower latitudes.
They are found, as a rule, where the mean summer
temperature is over 50°, where the rainfall is reason-
ably heavy, and is well distributed, and where soil
and other factors are not unfavourable. Forests are
characteristic at the present time of the rainy west
coasts of the continents, as in southem Chile and on
the northem Pacific coast of North America; of
much of the interior of North America and of Siberia;
of the Scandinavian highlands. On the north, the
great forest beits merge into the tundra through a
zone of scattering trees and stunted bushes. On the
south, they grade into the open steppe country of the
Continental interiors. Much of the temperate zones,
except where too dry, was originally forest-covered,
but the trees have been gradually cleared away and
an open country, devoted to agriculture, or the seat
of modem manufacturing and industiïal settlements,
has taken their place. The southem portions of the
great forest beits, because of their more favourable
climates, are better adapted to agriculture than
the northem portions, and are therefore first attacked,
284
CLIMATE
as is now the case in Siberia. The more severe cli-
mate of the latter, and their greater inaccessibility,
will help to preserve them from destruction for farm-
ing districts, with the primitive life of the trapper
and woodsman as their distinguishing characteristic.
The temperate zone forests, hampering man’s move-
ments, preventing dense population, and being re-
placed by more profitable farming country, have
thus gradually been driven back from the lowlands
onto the mountains and highlands of Europe, where
scattering forests alone remain. These are in most
cases protected by govemment. In the United
States, similar clearing has been going on, with simi-
lar consequences. Many of the forests which still
remain on the mountains have been set apart as na-
tional forest reserves, in order that they may serve
as regulators of water supply and as parks
for future generations. The slow spread of the
white population in the United States, from the
originally forested eastern section where it so long
had its seat, to the open country farther west, was
certainly in part due to the great difficulty which
the early settlers experienced in clearing away
the forests which they found on the Atlantic
slope. A larger population, better means for clear-
ing the forests, and improved transportation, later
changed this.
The foregoing statements must not, however, lead
us to jump at the conclusion that all open areas were
once forested, and thus to infer that a supposed de-
LIFE OF MAN IN TEMPERATE ZONES 285
forestation, which may never have taken place, has
produced a change of climate which has not been
proved. Many such cases have been reported for the
sub-tropical belt of the Mediterranean, and for South
Africa, but sub-tropical climates, with their dry sea-
son and light rainfall, are not favourable to heavy
forest growth. It is significant that the ancient
Greeks imported their most valüable woods from the
north.
Before the forest cover—the natural product of
soil and favourable climate—is cleared away, man is
chiefly occupied in hunting fur-bearing animals in
the colder latitudes; in fishing, and in lumbering.
The latter occupation is greatly facilitated by the
winter snows in northem latitudes, which make sledg-
ing easy, and by the spring freshets, which carry the
logs down to the saw-mills. Where there is no snow,
the difficulty and expense of getting out the timber
are usually considerably greater. The woodsman’s
life is primitive and hard, and retains many nomadic
tracés. The resort to “ the woods ” for hunting and
fishing by a good many people from the north tem-
perate zone for a part of the year brings for a time a
relief from the restraints of civilisation, and the rest
that comes from a return to more primitive condi-
tions of life. There is a considerable seasonal change
of occupation among the lumbermen of the northem
United States and of Canada, many of them becom-
ing farmers or sailors in summer. Industries which
depend upon a supply of lumber, such as paper and
-
286
CUMATE
pulp mills, shipbuilding, fumiture, carriage and bar-
rel manufactories, and the like, are often found on or
near the streams down which the logs are floated.
The simple log hut of the early settler in the Ameri-
can forest is one of the most typical forest dwellings,
which are naturally built of wood. The Japanese
houses of bamboo and wood are not unsuitable in a
region of tree-growth, of a modified Continental cli-
mate, and of earthquakes. Forest fires are often
very destructive, not only to the trees themselves but
to the wooden dwellings in the forest.
Fish and game are the natural food of forest peo-
ples, and clothing is chiefly made of fur or leather.
Forest products are brought to the edge of the forest
for sale or exchange. Thus the trappers in North
America played an important part in the early history
of that continent. Settlements, which were originally
trading posts, grew up along the streams, and
later became towns and cities. Almost all the large
cities of the north Pacific coast of the United States
owe their prosperity to the lumber industry, and the
same is true of other cities in or near the forested
portions of the country east of the Rocky
Mountains.
The dense Alaskan coast forests, which extend far
north where the moisture, even without high tem-
peratures, is favourable to them, have to-day certain
noteworthy effects on the native Indian tribes who
live along their borders. The density of vegetation
and the difficulty of agriculture force them to turn
LIFE OF MAN IN TEMPERATE ZONES 287
to the sea, on which they spend most of their time,
on which they travel, and from which they obtain
their food. They become expert canoe-builders,
sailors, and fishermen; are finely developed in the
upper portions of their bodies, but spend so much of
their life in their boats that they dislike walking and
are poor hunters and porters. Their food, and the
material for some of their utensils and implements,
they secure from the sea. They wander about to dif-
ferent fishing-grounds, living a more or less nomadic
life; some of them even going into the State of
Washington in harvest-time. It is an interesting
fact that the best canoes are built by the Indians who
live in the most stormy locations, and these same peo-
ple are also the best sailors. On the coasts of South-
ern Chile the dense forests have kept the population
close to the sea; have made clearing for farming dif-
ficult, and have resulted in making lumbering, hunt-
ing, and fishing the chief occupations. Darwin
reported of this region that the constant rains keep
everything so wet that to clear the forest by fire is
almost impossible.
Foreat Clearings. Man gradually makes clearings
in the virgin forest, and then cultivated crops take
the place of the natural tree-cover, except where ex-
tremely favourable conditions for tree growth, or
poor soil, or steepness of slope, make forests more
profitable than agriculture. At present, much of the
population of the civilised world lives in such clear-
ings. Where the clearings are small, as in parts of
288
CLIMATE
Scandinavia, the life is simple, combining lumbering,
hunting, and fishing of the forest with agriculture.
If the sea is near by, boat-building, as in Norway,
also becomes an important industry, with deep-sea
fishing and sailing. Simpler industries, like wood-
carving and match-making, are also found. Com-
munities are scattered, and are largely independent
of one another. Each community is selfsupport-
ing, and each individual is more or less of a “ Jack-of-
all-trades.” Isolated clearings, where civilised man
is making the first inroad into the primeval temper-
ate forest, may still be seen in several parts of North
America, and will become increasingly common in
the Siberian forest belt.
With the destruction of the forest and the growth
of agriculture, with settled places of abode and a
reasonably certain food supply following steady,
careful, and intelligent labour, comes the gradual ac-
cumulation of a surplus, and the increasing diversity
of interests and occupations which characterise the
modem, highly civilised community. Here we find
a very complex life, with industries and manufactures
of all sorts; where raw materials and supplies are
imported from other lands and climates and exported
to them, and where the immediate climatic control
often becomes difficult to see. It is under such con-
ditions that civilised man lives to-day, using the
products of the forest, the farm, the mine, the sea,
the lake, the river; making the most of his opportuni-
ties; overcoming more and more the disadvantages
LIFE OF MAN IN TEMPERATE ZONES 289
i
!
of his immediate surroundings. It remains a fact,
nevertheless, that one of the most important Controls
in determining the location of modem industries, next
to neamess to materials and markets and water-
power, is climate.
The Steppes. In the intermediate beits, between
the heavier rainfall of the forested districts and the
deficiënt rainfall of the deserts, come the grass-lands
of the temperate zones, commonly known as steppes
(“unwooded tracts in middle latitudes, of consider-
able extent and covered with useful vegetation”).
These are found where the rainfall is small because
of distance from the sea, or by reason of the rain-
shadow effect of enclosing mountains, and over
broad, more or less level topographic areas, of fairly
uniform climatic conditions. The general severity
of the climate, the small rainfall, the shortness of
the growing season, and other factors, such as high
winds, favour grass rather than tree growth. The
central Asiatic plateau, except where so arid as to be
a true desert, with uniformity of climate and of popu-
lation, is the great steppe region of the world.
Southern Siberia, Southern Russia and Hungary,
and parts of Arabia, Persia, and Asia Minor belong
to this same area. The Great Plains between the
Rocky Mountains and the lOOth meridian are classed
as steppes, as are the grass-lands of eastern temper-
ate South America. The Asiatic steppe is extremely
unfavourable, so far as occupation and development
by man are concerned. At the centre of a great
*9
290
CLIMATE
overgrown continent, with the trade of the world
naturally passing around it, largely by water, rather
than across it; with few rivers and deficiënt precipita-
tion, the effect on man, whatever may have been the
conditions of the past, is such as to depress, retard,
overcome him. Civilisation there lags behind that in
the rainier lands of the temperate zone. The grass-
lands of North America, it may be noted, have the
advantage of being a narrow belt between two well-
watered and fertile regions. The dry season
scorches the grass and dries up the rivers; the spring
rains bring out the carpet of grass and flowers.
Winter storms and cold sweep over the steppe, often
fatal to man and beast.
The primitive inhabitants of the Eurasian steppe,
like the Kirghiz, Mongols, Kurds, are nomads, mov-
ing about during the summer in search of water and
pasturage for their animals. Their migrations often
take them to the higher country, where there is more
chance of finding water, and where the grass is bet-
ter. A dry year forces migration into the adjacent
rainier districts. In the colder months the people
settle down in more permanent abodes. Thus also
we find the inhabitants of the Hungarian plain
townspeople in winter and semi-nomadic farmers in
summer. Professor W. M. Davis has noted the use
of small farm-houses on wheels in Bosnia, which
“ are drawn forward on the plain in the dry season,
so as to stand near the pasture fields; and back again
towards the higher margin in the wet season.” The
LIFE OF MAN IN TEMPERATE ZONES 291
driving of cattle from Argentina across the moun-
tains into Chile during the dry season is another in-
stance of seasonal migration in search of pasturage
in grass-lands.
The primitive steppe-dweller depends on his flocks
and herds for his food and clothing, and for his tent-
coverings and utensils. From their wool, or hair, he
makes his cloth, or carpets. The summer dwellings
of the Asiatic steppe-dweller are usually feit tents,
adjustable, portable, skilfully constructed. These,
with simple household goods made principally of
leather, at once the most available and most useful
material, are easily transported from place to place.
In winter, encampments are carefully selected
where there are water and grass, and where hay
is collected. The winter dwellings are better built,
of the willows or reeds found along the streams, and
the animals are sheltered against cold and storm.
As on the Coastal desert of South America, so here,
a common fuel (in winter) is the dried dung of ani-
mals. Horses are a precious possession, essential to
the wandering life of people some of whom call
themselves The Horsemen (Kazak). The trade of
the Asiatic steppe is carried on with China on the
one side and Russia on the other. Hides and other
products obtained from the flocks and herds are ex-
changed for tea, flour, opium, clothing, etc. In-
dependent, conservative, and proud, the natives
retain their traditional customs, and resist the en-
croachments of civilisation. The life of man in
I
292
CLIMATE
steppe and in tundra has many points of resem-
blance, but the steppe is the more favourable to
improvement.
The early life of the white man on the Great Plains
of North America has been similar in many ways to
that on the Asiatic steppes. Immense herds of cattle
have grazed at will over a vast extent of territory,
driven here and there in search of pasturage and wa-
ter, and tended by semi-nomadic cowboys spend-
ing most of their lives in the saddle. The gradual
destruction of the natural grass forage by over-stock-
ing, and by the introduction of sheep, has not in-
frequently led to armed conflicts between those in
charge of different herds of cattle. The United
States has also illustrated what has been observable in
other lands, viz., the conflict between the divergent
interests of those who want grass-lands for agricul-
ture and those who want them for grazing. In
North America the conflict was not waged with
bloodshed, but history furnishes examples of the war-
like encroachment of pastoral nomads into the peace-
ful farming communities on the borders of the steppe.
China, for example, was invaded by steppe-dwellers,
as was Europe at one time; even to-day, Kurds and
Armenians are struggling in a similar way. In the
United States, the facility of communication and the
rapid advance of population from the east have led,
in recent years, to a considerable change in the use
of certain portions of the Great Plains steppe region.
After an almost exclusive use of these plains for cat-
LIFE OF MAN IN TEMPERATE ZONES 293
tle, farming without irrigation was tried over their
central portion in the latter part of the decade 1880-
1890, during and closely following a series of years
with a rainfall somewhat above the average. The
experiment proved to be a failure when a series of
drier years followed. Since then, local irrigation by
means of wind-mills has been introduced to a con-
siderable extent, and diversified farming under irri-
gation, with cattle-raising on a much smaller scale
than formerly, has been found to be a far more profit-
able undertaking than farming on a large scale with-
out irrigation. The cattle are fed, when necessary,
with alfalfa or other forage raised for that purpose;
are bred under supervision, and are protected against
the severe winter storms and cold. The climatic
limitations of the Great Plains are now clearly re-
cognised. By far the greater portion must forever
remain pastoral, but where irrigation can be prac-
tised, farming and cattle-raising together are more
profitable than either alone. Irrigation, together
with the proper preparation of the soil and the plant-
ing of crops suited to the climate, has worked a com-
plete change in the appearance and in the economie
value of many parts of the Great Plains. The large
modern cattle ranch in the western United States is
very different from the wandering cattle herd of a
few years ago. There are summer - and winter
ranges for the stock, the winter range being sheltered
as much as possible. On a well-equipped ranch, a
barometer is watched as carefully as on board ship.
294
CLIMATE
When a storm is expected, the sheep or cattle are
brought to shelter if possible, or if not, are driven to
windward, so that they will be driven home by the
storm. In Australia the grass-lands have been oc-
cupied by British sheep-owners, employing native
stockmen, and the conditions of life are much like
those of the ranchmen on the Plains of North
America.
Obviously, wherever irrigation is possible, steppes
become more valuable for farming than for grazing.
There is a limit to the water supply, whether that
come from rivers or from underground, and an in-
creasing population, with increasing demands for
water, must in time reach the limits of the supply.
In many of the western states of the American
Union, where with increasing population the need of
irrigation has been feit more and more, much litiga-
tion has arisen concerning the right to water. The
difficulties have come in great measure from the fact
that the laws were imported from rainier regions,
where irrigation was unnecessary. On the Asiatic
steppes, Russian influences are encouraging irriga-
tion and agriculture. As a rule, the steppes of the
temperate zone have been cultivated where settled
by people who had formerly been farmers in more
humid regions.
The wide expanse of the steppes, with their un-
obstructed surface, situated as they usually are in
the extreme climates of the Continental interiors, ex-
posés them to sudden temperature changes. The far-
LIFE OF MAN IN TEMPERATE ZONES 295
reaching sweep of cold storm winds from higher lati-
tudes, such as the cold norther or blizzard of North
America and the buran of Siberia, may destroy
thousands of cattle in a few hours and not infre-
quently human lives as well. Depressing hot winds
from lower latitudes, which carry high temperatures
far poleward, sometimes injure crops by their heat
and dryness. In dry times, fires once started have
a free sweep over the open steppe country.
Climates and Crops in the Temperate Zones.
The variety of climates found over the temperate
zones, especially in the northern heimsphere, is very
large, ranging from the modified marine climate on
the west coasts to the extreme Continental of the in-
teriors and the modified Continental on the east
coasts, and also varying greatly with latitude. No
such simple discussion according to climatic sub-
divisions is possible as in the case of the tropics.
Forests are found on the rainy west coasts and also
in the interiors. Agriculture is practised where the
forest has been cleared, and also on the steppes and
even in the deserts, wherever irrigation is possible.
These variations in climate from east to west and
north to south across a continent, are such as to
necessitate great differences in the season and
methods of agriculture, and in the crops that are
grown.
In the sub-tropical beits, favoured as they are in
many ways as to climate, man fights against frost in
Califomia; protects his crops by walls or hedges
296
CLIMATE
against high winds, as in the Azores, in Malta, and
in Southern France; manufactures artificial ice in
Falestine; retards the ripening of his fruit under the
spring sun by screening it. The latter is an interest-
ing phase of man's effort to make the most of his
climate, regulating it so far as may be possible. In
parts of Italy it is customary to cover the lemons
with sereens of cloth or rushes, so that they may not
ripen until the summer demand is at its height in
England and America, and prices are good. The
equable climate of the Pacific coast of the United
States makes it possible to keep farm animals out-
doors most, or even all, of the year, thus saving the
expense of bams and stables necessary in more rigor-
ous climates. In summer on this coast, advantage is
taken of the dry season to leave wheat out in sacks,
sometimes for weeks at a time, without much fear of
damage by rain. This is a great convenience for the
farmer. Raisins are usually dried outdoors, although
some of the larger growers are now introducing dry-
ing houses. The damage done by one rain is so great
when raisins are partially dry, that the field labourers
at such critical times, when rain is forecasted, insist
on being paid extra high wages to bring in the fruit.
The kind of agricultural machinery depends largely
upon conditions of climate and crops. The com-
bined harvester and thresher used in California could
not be successfully employed under other conditions
of dryness and ripeness of the grain. The use of this
machine is much restricted farther north, in Oregon
LIFE OF MAN IN TEMPERATE ZONES 297
and Washington. It may here be noted, in passing,
that in Norway agricultural machinery has been well
received on account of the shortness of the summer
and the need of accomplishing outdoor work quickly.
Cereals are a winter erop in the regions of winter
rains, and many fruits can be very successfully
grown, such as lemons, figs, olives, oranges, etc. The
sub-tropical vine-growing districts of Italy, Spain,
southem France, California, southem Australia, and
Cape Colony are natural centres for the wine industry.
The great cereal lands of the world are found in
the Continental interiors, in the regions of summer
rains, where the precipitation is sufficiënt. Roughly,
between latitudes 40° and 52°, other conditions be-
ing favourable, we find the principal wheat belt; hut
wheat is cultivated much farther north, for example
in Asia, and also farther south than the above limits.
Barley grows over a much wider belt, both poleward
and equatorward; oats grow north of wheat, and corn
grows south of it. In the higher latitudes, with
shorter summers, it is more and more difficult for
cereals to ripen. All over the cleared farm-lands and
cultivated steppes of the temperate zone, droughts,
or excessive rains, or frosts, or other harmful condi-
tions are always to be feared. On the whole, the
struggle against adverse conditions of climate, and
weather, and soil, is so hard that it constantly de-
mands man's best energies, his best methods, his best
implements.
Climate has, in a large way, set apart certain great
298
-
CLIMATE
areas where agriculture may be best carried on.
Similarly, it has determined that one area shall be
adapted for grazing and another for forests. For-
ests will always grow chiefly in the rainier regions,
because, although trees can be made to grow, by care-
ful selection and proper care, over a good deal of
steppe country, they will always grow better, and
faster, and more cheaply, where the rainfall is heavier.
A map of the products of any country, in crops, or
cattle, or forests, will show, when compared with a
rainfall map, the broad, general relations which are
here referred to. There is, it may be noted, often an
intimate connection between a product of one sort
and one of another sort, as, for example, in the case
of hogs in the United States, which are raised in
largest numbers in the region which produces the
most corn, on which the hogs are fed. The climatic
control of occupations is beautifully illustrated in
Chile. In the rainy south, the forests, with lumber-
ing and fishing; in the arid north, the deserts, which
would be uninhabited were it not for the nitrate and
other mineral deposits which have given the region an
extraordinary value; in the central portion, with a
climate neither too wet nor too dry for agriculture,
we have the great farming, cereal, and stock-raising
districts.
The Deserts. In the Continental interiors, where
the distance from the ocean is great and the endosure
by surrounding mountains is effective in intercepting
the moisture brought by the winds, grass-land is
\
LIFE OF MAN IN TEMPERATE ZONES 299
replaced by sparser and sparser vegetation; steppe
merges into desert; population decreases more and
more. Such arid regions are found in the deserts
of south-eastern Califomia, Arizona, and New Mex-
ico; in northem Mexico; in the interior of the great
overgrown continent of Asia. These deserts are
the extreme product of Continental climate. With
moderate or cold winters and hot summers, the life of
man in them is controlled in much the same way as
in the deserts of the tropics.
No more striking illustration of this control over
the primitive desert-dwellers of the temperate zone
has been given than in the study made by McGee of
the Papago Indian tribes of Southern Arizona. “ The
Papago prefers to live where other people famish;
he is able to do so by reason of his remarkable adjust-
ment of his habits, his food and raiment, his indus-
tries, his social organisation, to a peculiar assemblage
of conditions.” These people can go long without
food and water; in emergencies they secure water
from the barrel cactus (biznaga) 1 : they chase rain-
storms for miles across the desert, and plant wherever
water or damp soil is found; their houses, built of
mesquite saplings, protected against the ravages of
cattle by thorns, or of adobe, are located near damp
soil, or a water supply. The Papago’s life is nomadic
for much of the year because he migrates in search of
the means of subsistence, of which, as McGee puts it,
1A good illustration may be found in PI. xviii of the "Desert
Botanical Laboratory of the Carnegie Institution,” 1903.
300
CLIMATE
“the first, and the second, and the third are water,
water, water, to alleviate his own thirst in the sun-
parched deserts, water to sustain his horses and burros
and kine, water to vivify the plants of which man and
his creatures eat.” The seasons of planting and of
harvest depend on storms, come when these may;
when the local water-supply fails, water is carried
long distances on burros, or on the head; the springs
are protected by a corral or stockade made of cactus,
and even of the dried carcasses of bulls killed in the
battle for water; only the simplest arts of pottery-
making are practised. All this shows a climatic
control of which no better illustration can be found
anywhere in the world. The thick adobe walls of the
Indian dwellings of the south-western United States
in general are well adapted for keeping the inside
temperature equable, in spite of the large diurnal
ranges outside. The Pueblo Indians show the in-
fluence of climate in their use of stone, and in the
absence of wood in their buildings and utensils. Heat
and cold split the rocks of their mesas and furnish
material for building. The reckoning of a man’s
wealth according to the number of horses in his pos-
session; the open and easily-transported huts óf the
Navahoes, which furnish sufficiënt protection against
the heat and the wind of the hotter months, with more
permanent winter houses of adobe, better fitted as a
protection against the severe weather of the colder
season; the rain-dances and rain-gods of the south-
westem United States,—all this is but a repetition of
LIFE OF MAN IN TEMPERATE ZONES 301
what is found among the native tribes of the hot
tropical desert. It has been well said by one
writer that u the whole religion of the south-west
may be summed up in a single phrase—a prayer for
rain.”
In the arid interior of Asia we see the same no-
madic life, the same difficulty of travel, the same semi-
pastoral, semi-industrial population along the borders
or in the oases of the desert, as in the tropics. But in
the temperate zone deserts there comes always the
greater need of protection against more severe cold.
It has been believed by many writers that a Progres-
sive desiccation in central Asia drove the inhabitants
out onto the lowlands, and was followed by the
Asiatic invasion of Europe; but there are not want-
ing those who do not believe such desiccation proved,
and who doubt, as H. J. Mackinder has said, whether
these changes, even if proved, have “ in historical
times vitally altered the human environment.”
In time, civilised man will make use of every avail-
able drop of water which is supplied in these arid re-
gions, whether by streams, or in the form of rain, or
from underground, and the irrigated desert will de-
velop in man those qualities of coöperation which have
been conspicuous in the irrigated communities of
Peru, among the Indians of the south-westem United
States, in ALfrica and in Asia, in Utah and in Cali-
fornia. Where every drop of water has a money
value, there results a unification of interests in the
common water supply which is as striking as it is
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CLIMATE
interesting. But there is a limit to the population
whose needs can be supplied in these deserts, even
when every available water supply is drawn upon;
and the temperate deserts, like those of the tropics,
must always remain sparsely populated, as a whole,
with their inhabitants collected here and there around
oases, or in the larger, modem, irrigated areas. The
immense public irrigation works recently completed,
or now being carried out by the United States gov-
ernment, furnish striking illustrations of the effective
use which civilised man now makes of water in an
arid region, while the Mormon irrigation, practised
in Utah, still remains a model of what can be accom-
plished by individuals working in harmony.
A typical desert industry is the harvesting of salt,
as from Great Salt Lake in Utah, at Salton in the
California desert, in Turkestan, Patagonia, and
China. In the last-named country salt was formerly
used as money, the salt industry being a govemment
monopoly, protected by a prohibition of the importa-
tion of foreign salt. In Chinese Turkestan blocks
of rock salt are sometimes used in building walls, and
huts built of rock salt have also been reported. The
difficulty of securing water in the temperate deserts
is often serious. Baku is to-day supplied in part
with water obtained by distilling the brackish waters
of the Caspian Sea.
Railroad construction and operation in the tem-
perate deserts, e. g., in Arizona and south-eastem
California, or on the new trans-Caspian railroad in
LIFE OF MAN IN TEMPERATE ZONES 303
Asia, and on the projected trans-Australian railroad,
have to contend with difficulties similar to those in the
tropical deserts, to which reference has already been
made. A curious effect of sand-blasting is noted
from the California desert, where the telegraph poles
along the railroad are so wom near their bases by the
blowing sand that they have to be protected by
piles of stones. The Southern trans-continental rail-
roads of the United States, which traverse the hottest
and dustiest part of the interior desert, lose much
travel in summer because passengers pref er the more
northerly, cooler, and less dusty joumey.
Mountains. The mountains of the temperate zones
are often forest-covered on their upper slopes, with
pasture lands farther down, and below these, the
lower slopes are used for agriculture. The variety
of occupations within a restricted area is thus consid-
erable, e. g., lumbering, forest industries, and hunting
above; farming and fruit-growing below. Moun-
tains which rise from steppes or deserts have the char-
acter of oases, or islands. The general conditions
of climate and of life on mountains are so different
from those on lowlands that it is not surprising to
note the differences, often observed, between moun-
tain and lowland peoples. The decreasing mean tem-
perature, the inaccessibility, the smaller amount of
land available for profitable use (except in the case of
mines), and the decrease in plant and animal life for
food, suffice to set a limit of height to the habitability
of these mountains by man. Human settlements, as
304
CLIMATE
a whole, therefore decrease in number and impor-
tance with increasing altitude, except where mineral
wealth or forests are an attraction.
The successive vertical zones or beits of vegetation
vary much in altitude above sea-level, according to
the slope on which the plants grow, the warmer
Southern slopes (in the northern hemisphere) giving
vegetation more favourable conditions at a greater
altitude than the northern. A similar effect of
favourable exposure is commonly seen in the dis-
tribution of population in mountainous districts.
Human settlements are usually found at greater ele-
vations on the sunnier slopes, where the conditions for
agriculture and for grazing are most favourable,
but temporary lumbering or mining operations may
locally induce higher settlements on the shady slopes,
and more favourable rainfall on the latter may also
bring about a departure from the general rule. The
average upper limit of settlements in the Alps coin-
cides fairly well with the upper limit of grain. It is
reported that in. the Oetz Valley, in the Alps, consid-
erably more than 75 per cent. of the population live
on the sunny side of the valley. Lugeon’s study of
the principal valley of the canton of Valais, between
Martigny and the Rhone glacier, has brought out
similar interesting facts. In a certain part of this
district, the villages, with but one or two exceptions,
are on the sunny side. In fact, a certain distinction
of classes results from this difference. There is de-
veloped an aristocracy of the sun, so to speak. The
LIFE OF MAN IN TEMPERATE ZONES 305
people on the sunny side are, on the whole, more pros-
perous and better educated, and look with some con-
tempt upon the people on the shady side. The
marked avoidance of the lower parts of valleys in the
Alps, and in other temperate mountain regions, and
the building of houses on the mountain slopes or the
hill-tops, depend upon the frequent occurrence of
inversions of temperature. Löwl has pointed out
that in parts of the Alps, terraces, fan-cones, and
other topographic forms elevated somewhat above
the valley floors, are thus sought out as locations for
houses.
The value of land is obviously determined largely
by its position with reference to slope, exposure, and
liability to frost occurrence. Southem slopes (in
the northem hemisphere) are usually more desirable
as well as more expensive, and many examples might
be given of the difference in value of land which
is more exposed to frost and of that which is less
exposed. California fumishes many excellent ex-
amples. A grain ranch lying in a frosty pocket may
there be next to land which is practically frost-free.
The latter is worth two hundred or more times as
much per acre when well established in oranges. The
kind of erop which can be grown, and hence the
financial return, also depends largely upon exposure
to sunshine and frost, protection against destructive
winds, and the like, as well as upon soil.
It is a characteristic habit in many parts of the
temperate zones to drive cattle up onto the higher
306
CLIMATE
slopes of the mountains for pasturage in the summer
months, whereas, on the approach of the winter, they
are brought back to the permanent settlements be-
low. Examples are found, among other places, in
Switzerland, where the cattle and goats, with their
herders and shepherds, spend the summer far up on
the alpl in S weden and Norway; in south-eastem
France; on the Balkan peninsula; among certain In-
dian tribes and also on some of the great cattle ranches
of the United States; in much of the plateau bountry
of Asia, as on the Pamir, and in parts of Armenia,
the Thian Shan, and the central Himalayas; in north-
em Africa, and in the Urals. The modem develop-
ment of summer resorts in mountains is but another
manifestation of this seasonal control of migrations
by the climatic conditions resulting from the presence
of mountains. Special cases of a peculiar kind are
found in the Sary-Tur and Thian Shan mountains,
among the Boginzes and the Kirghiz, who in winter
drive their horses and herds up above the level of the
winter clouds and snows to the upper pastures, which
are well waterpd by the summer rains, and furnish
abundant grass for fodder. Again, in Sistan, Ells-
worth Huntington reports an occasional migration
down from the relatively cool mountains during a
dry season, and across the desert to the lake waters
beyond. But these are exceptions to the general
mie of upward migrations in summer.
The forests above the grass zone are frequently
the last resort of wild animals which have retreated
LIFE OF MAN IN TEMPERATE ZONES 307
from the lower slopes, and hunting expeditions in
search of this game are often made.
Mountain peoples have special conditions to meet.
Their dwellings are usually better built and furnish
better protection than is the case on the lowlands. In
some cases the people live almost or quite under-
ground, in order to secure the maximum protection
against cold, or heat, or high winds. In Kashmir
some of the natives carry about, under their loose
clothing, earthenware pots filled with live coals, to
keep them warm. Severe winters on mountains, with
little or no possibility of doing outdoor work, pro-
mote home industries. Foehn or chinook winds lo-
cally favour the raising of special crops or fruits;
melt the snow rapidly, so that cattle may find susten-
ance through the winter; or necessitate strict regula-
tions against fires, as in parts of Switzerland. The
bora interferes with shipping along the eastern shore
of the Adriatic. Mountain and valley winds some-
times locally attain such violence as to make travel or
habitability difficult or impossible.
A peculiar custom which prevails among certain
native tribes of the Himalayas, and which is an
interesting result of climate, has been reported
by Ellsworth Huntington (in manuscript). Certain
Kashmiris, who live in the Himalayas between Kash-
mir and Ladakh, at an altitude of about 10,500 feet,
spread earth on the snow in order to make the snow
melt more quickly.
“ Those whom I saw,” reports Huntington, were Kash-
308
CLIMATE
miris who had come to the country within a generation or
two, and had learned the practice from the long-settled
Ladakhi or Tibetan inhabitants. The snow, April 11, 1905,
was unusually deep, about 10 feet, and was not expected,to
disappear for nearly two months, some two weeks later than
usual. In the drier region of Ladakh, nearly to the east,
the practice is followed by people living as high as 14,000
feet. Sometirqes a snowstorm covers the layer of soil on
the old snow, and new soil has to be gathered and spread.”
Travel and transportation meet with many ob-
stacles in mountains, apart from the natural difficul-
ties which come from steepness of slope and from
forest cover. In all latitudes where snow falls in
winter, obstruction by snow-blockades is a serious
matter, and the question whether it is better to tunnel,
or to build above the ground and keep the tracks clear
by means of ploughs and snow-sheds, is an important
one for the engineers to settle. The northem trans-
continental railroads in North America, where they
pass over the western mountain ranges, are protected
for long distances at critical points by snow-sheds.
These, being of wood, are apt to take fire, and fire
watches and fire apparatus are provided for such
emergencies. Below the latitudes where snow
falls in considerable quantities, sheds are not needed.
Some railroads in mountains are abandoned alto-
gether in winter. Floods and washouts, landslides
and avalanches, are additional handicaps. The fa-
mous Uspallata Pass, between Chile and Argentina,
is not used by travellers in winter, on account of the
LIFE OF MAN IN TEMPERATE ZONES 309
snow. Traffic then goes by steamer, by way of the
Strait of Magellan. Fierce, cold winds, and the alti-
tude, have been effective barriers in keeping Tibet so
long isolated, and will remain effective barriers in the
way of any movement of troops across the Tibetan
plateau.
Cümate and Weather: Some Mental Effects. The
frequent and sudden weather changes of the temper-
ate zones affect man in many ways, as do the larger
seasonal changes. The relations between weather
and conduct have frequently been investigated.
Professor E. G. Dexter has made an extended em-
pirical study of the effects of the weather in relation
to deaths, suicides, the number of errors made in
banks, and misdemeanours generally. It appears, as
one of the most interesting. general condusions, that
physically exhilarating weather conditions are accom-
panied by an abnormal prevalence of excesses in de-
portment, while deaths, suicides, and errors in banks
show a decrease. So many indirect effects come into
play in these conditions that care must be taken not
to draw too hasty condusions. Thus H. H. Clay-
ton has pointed out that errors in banks may be more
likely on cloudy days because of the greater difficulty
in seeing figures, and also that fine weather tempts
people out of doors and thus brings them into con-
tact with others, giving opportunities for crime.
Light wind movement seems to be accompanied by
fewer misdemeanours in schools; low relative humidity
by a larger percentage of misdemeanours; great cold
-
310
CLIMATE
by more suicides, and so on. Bertillon has collected
data on suicides and seasons in France, and Leffing-
well has investigated illegitimacy and the influence of
seasons on conduct in Great Britain.
The difference in the effects of a bright, crisp day,
when work is well and quickly done, and of a dull,
depressing, and enervating day is well known. A dis-
mal day is a dies mali. Strong cyclonic winds, blow-
ing polewards from lower latitudes, are characteristic
of the temperate zones, and are proverbially disagree-
able and irritating, in strong contrast with the cooler
winds from higher latitudes. The sirocco in Italy;
the solano in Spain; the norte in Argentina, for ex-
ample, are such winds. The sirocco has been described
as “ not fatal to human life,” but “ deadly to human
temper.” In Spain there is a proverb, “Ask no
favour during the solano.” The nervous effects of
the dry foehn and chinook are well known. The
zonda of the Argentine is reported as not infrequently
making people temporarily insane, and leading to
suicide. Many other mental effects of the weather
might be noted.
Climate, Weather, and Military Operations. His-
torical consequences of great importance have fol-
lowed from special conditions of climate or weather.
Maguire’s OutUnes of Military Geography (Cam-
bridge, 1899) contains a chapter on the influence
of climate on military operations, but this subject has
hitherto received little attention. More recently,
Bentley, in a presidential address bef ore the Royal
\
LIFE OF MAN IN TEMPERATE ZONES 311
Meteorological Society, London, considered the
matter. A few illustrations only can here be
given.
The fleet of Xerxes was lost in a storm on the
coast of Greece. In 54 b.c., owing to a preceding
drought and scanty harvest, Caesar was obliged to
scatter his army in separate winter quarters, and in
this situation one of these isolated bodies of Romans
was attacked and destroyed. The consequences came
near being very disastrous for Caesar. A storm de-
stroyed the Spanish Armada. The French Revolu-
tion was precipitated by a severe winter. Napoleon
was defeated in 1796, owing to the ground being too
heavy for the movement of the French artillery. In
1796, also, Gen. Hoche’s fleet, sailing for Ireland,
was scattered by a storm. The terrible winter retreat
of the French from Moscow fumished a vivid illus-
tration of the' strength of the two invincible Russian
generals, January and February (to use a Russian
expression). The battle of Waterloo was postponed
on account of a heavy rainfall. The siege of
Sebastopol fumished another illustration of the suf-
fering which a severe winter may produce. The
“ Boxer ” outbreak in China, in 1900, was precipi-
tated by a scarcity of rain in the preceding autumn,
bringing on destitution and famine, and driving the
people to pillage and robbery. During the fighting
around Tientsin, early in July, the situation of the
allied troops was very critical when a torrential rain-
fall compelled the Chinese to retire. During the Boer
312
CLIMATE
war there were many instances of weather Controls
over military operations. On January 9, 1900, a
heavy rain checked the fighting near Ladysmith, and
cloudy weather often prevented the use of the helio-
graph in communicating with Ladysmith. During
the recent British campaign in Tibet, great difficulty
was experienced at the higher altitudes, owing to the
hardening of the oil in the guns on account of the
cold, and the low boiling point made it difficult to
cook food properly in the absence of cooking utensils
adapted for use at low pressures. In the Russo-
Japanese war, the cold and heat and rain made them-
selves feit as powerful factors in the campaign.
The effect of even one rain may be far-reaching.
It has been said that a shower of rain acts like a wet
blanket on a mob. Numerous recent illustrations of
the truth of this statement are available. A rain in
Paris on the day of the Dreyfus verdict, in Septem-
ber, 1899, doubtless helped to prevent, if it did not
actually prevent, an outbreak. During a great strike
in Moscow at the end of January, 1905, a snowstorm
greatly helped the authorities in keeping the people
off the streets. Again, on April 6, 1906, at St.
Petersburg, a steady downpour of rain all day pre-
vented an open-air meeting which would doubtless
have led to conflict with the military.
Railroads. Railroads have reached their greatest
development in the Continental climates of the tem-
perate zones, and the influence of these climates upon
the construction and operation of these roads is far-
LIFE OF MAN IN TEMPERATE ZONEB 313
reaching, varied, and of the greatest economie im-
portance. Transportation by rail is necessarily
closely affected by weather conditions, for trains have
no protection against snow, or wind, or heat. The
extremes of heat and cold have a racking effect
upon all iron and steel work, and careful allowance
has to be made for this factor. Floods wash away
bridges, tracks, and ballast. In the Mississippi basin
of the United States, floods in 1908 cost the Santé Fé
Railroad alone $1,000,000. Stormy weather means
bad country roads, and this may prevent the trans-
portation of farm products to the railroads, and thus
result in irregularity in the supply of freight. It is
believed that were freight delivered regularly, the
railroads would find it possible to use less rolling
stock, with better returns.
Many of the most obvious climatic handicaps are
seen in the more northem latitudes of the north tem-
perate zone, where the winter brings snow and ice.
The trans-Siberian Railway was constructed with
great difficulty because of frozen soil, spring thaws,
and upheaved tracks. Across the rivers and across
Lake Baikal, rails were laid on the ice during con-
struction times. Later, the trains were carried across
the lake in winter on ice-breaking ferryboats. The
houses for the labourers were also built on the ice.
Work was greatly interrupted during the winter.
On the Great Lakes of North America, temporary
rails are laid on the ice during the ice-cutting season.
The new trans-Canadian railway lines will traverse
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CLIMATE
a region of severe cold in winter, but generally of
moderate snowfall, and although situated far to the
north, they will draw upon a splendid wheat erop,
favoured by the warmth and well-distributed rains
of summer. The snow-blockades on the northern
railroads of America led to the invention and use of
the ingenious and effective rotary snow-plough; to the
planting of trees along the right of way to serve as
snow-breaks, and to the construction of snow-fences.
In Siberia, the snow itself is occasionally piled up in
heaps by means of ploughs or shovels, and is thus
made to serve as a windbreak. The campaign of a
modem electric Street railway system, in an American
city, against the winter’s snow, is carefully planned in
the preceding summer, and every detail is worked out
beforehand. A mild, open winter in latitudes where
winter snowfall is an important factor in railroad
operation, means a saving of money, time, and labour,
which results in increased eamings and even in larger
dividends. The motive power which is otherwise
employed in fighting snow is then earning money for
the company.
In the warmer latitudes and drier seasons the blow-
ing sand and dust are disagreeable, and even delay
transportation at times. High temperatures and
heavy rainfall hasten the decay of railroad ties. The
growth of weeds on the right of way of earth-ballasted
roads is a considerable difficulty in many parts of the
temperate zones, as well as in the tropics. In the
United States, the Union Pacific Railroad has used
LIFE OF MAN IN TEMPERATE ZONES 315
a gasoline weed-burner, which scorches off the vegeta-
tion, and the salt water of Great Salt Lake, sprinkled
over the road-bed, has also been found to serve well
as a weed-destroyer.
The state of the weather sometimes fixes the load
of an engine, as in the case of freight trains running
west from Pittsburg, Pennsylvania. According to
the weather forecast of favourable, reasonably good,
bad, and very bad weather, the load of a freight en-
gine varies from 1750 tons to 1225 tons. The busi-
ness of railroads depends largely upon the season,
but the time at which these roads are generally the
most useful, and also the most overburdened, is after
harvest-time. Then, in the great wheat regions of
North America, the immense crops can with difficulty
be handled and stored, and the need of money to
“ move the crops ” not infrequently leads to financial
readjustment and stringency in the money market.
Transportation by Water. The oceans at the
equatorward margins of the temperate zones have
the light, variable winds and calms of the horse lati-
tude beits, with the seasonal change from trades to
westerlies, and back again. From the Mediterranean,
a fairly calm sea with few storms, came many of the
early navigators and explorers, doubtless tempted to
sea by the regularity and steadiness of their winds
and by the cleamess of the air which, before the days
of lighthouse, compass, and telescope, aided naviga-
tion by making it easy to see distant landmarks. In
the higher latitudes, the prevailing westerlies, blowing
316
CLIMATE
with moderate to high velocity and frequently
disturbed by storms, especially in winter, generally
favour voyages to the eastward, but are head winds
for vessels sailing westward. The voyage from
Europe to North America is not an easy one for sail-
ing ships, for, in addition to the head winds, there is
also the danger of ice and of fog on the Banks of
Newfoundland. The sailing route from Europe to
North America by way of the north-east trade, and
back, more directly, in the westerlies, makes effective
use of these two great wind systems. To keep clear
of ice and fog, the North Atlantic steamer routes at
certain seasons keep farther to the south, with the
disadvantage of lengthening the distance travelled.
Ocean currents, which are meteorological phenomena
because wind-driven, are important factors in con-
trolling the location of sailing routes. The voyage
around Cape Hom to the westward, in the teeth of
boisterous westerly gales, is much dreaded by sea-
men. Outward-bound vessels from England to
Australia find it convenient to sail by the Cape of
Good Hope, while on the homeward voyage they can
round Cape Hora to the eastward. By so doing
they have a good chance of fair winds all the way.
The most favourable weather condition for pass-
ing Cape Hom to the westward is the presence, dur-
ing the period necessary for rounding the Hom and
for Crossing latitude 50° S. in the Pacific, of a centre
of low pressure in the immediate vicinity of the Cape,
and not too far to the southward. This pressure dis-
r
LIFE OF MAN IN TEMPERATE ZONES 317
tribution gives north-east, east, and south-east winds
in succession in the case of a west-bound vessel which
passes the centre to the southward. The cyclones of
the westerlies are always more or less of a hindrance
and danger to shipping. Storm winds have, it is
true, accidentally led to the discovery of new lands,
hut stormy seas do not tempt man to sail upon them.
Protected harbours are naturally sought; unprotected
harbours are provided with breakwaters and docks;
low-lying coasts, like those of Germany and Holland,
are subject to damage and flooding, and even loss of
life, by storm waves and high tides. Even on the
borders of the temperate zones, in the sub-tropical
beits, the winter cyclones of the westerlies occasion-
ally give rise to gales dangerous to shipping, as on
the coast of California and of Chile. When a strong
norte blows at Valparaiso, as it sometimes does in
the winter season, the vessels at anchor in the har-
bour are obliged to steam or to be towed out into the
open ocean, in order to avoid being blown ashore.
The vessels in this harbour are anchored at both bow
and stern, always facing the north.
The freezing of harbours at the termini of the north-
em railroads is a serious handicap in many countries.
Ice-breakers are used by Russia at Vladivostock; and
at Hango, Cronstadt, St. Petersburg, and other ports
on the Baltic. Germany’s northern ports suffer more
or less from the inconvenience of ice in winter. The
closing and opening to navigation of the grain ports
is a matter of the greatest importance in the world’s
318
CLIMATE
grain trade. Canada is much handicapped by the
freezing of the St. Lawrence River. The trans-At-
lantic steamers change their sailings in winter to ports
that are accessible the year around. It has been pro-
posed to use an ice-breaker to keep the St. Lawrence
. open longer in the fall, and to break up the ice earlier
in the spring. The projected route from Canada to
Europe by way of Hudson’s Bay is obviously greatly
handicapped, if not rendered wholly impracticable,
by the winter ice. On the frozen Gulf of Finland a
considerable population of fishermen live on the ice
for several months; building houses for themselves
and abandoning for a time their usual occupation of
farming. On the frozen Neva, at St. Petersburg,
Street traffic goes on as on dry land; roads are made
over the ice; the streets are lighted; cars are run and
fairs are held.
Various Effects of the Weather. Effects of vary-
ing conditions of seasons and weather are observable
on all sides. The march of the seasons brings a suc-
cession of occupations. Thus farming, building,
painting, and outdoor work generally, are prominent
occupations in the warmer months in much of the
temperate zones. Lumbering, ice-cutting, and snow-
shovelling are distinctly occupations of the colder
months in the higher temperate latitudes in the United
States. In North America the harvesting of the
cereal crops calls for thousands of harvest hands
every summer, many of whom begin work in the south
and gradually work north into Canada, as the erop
LIFE OF MAN IN TEMPERATE ZONES 319
comes later and later in the season with increasing
latitude. It is worth noting, in passing, that the
wheat harvest in Argentina usually begins late in
November in the north, and progresses southward
until February; in India, the harvest begins late
in February in the south and progresses northward
until early in May. The Indian and Argentine
wheat thus come to market in what is known as the
“ dead season ” in the other wheat countries, and
therefore have an important effect on prices.
Rainfall, insufficiënt in quantity or poorly dis-
tributed, leads to a failure of the crops, and one or
more years of erop failure may bring on a general
financial depression. Even political overturns, as
has been shown by Clayton for the United States,
have been brought about by deficiënt rainfall result-
ing in short crops, and a similar occurrence has not
been unknown in England. Political consequences
following erop failure have been traced to the oc-
currence of destructive hot winds in Kansas in 1890
and 1891, which gave the Populist Party national
importance. The financial value of one rain, at a
critical time of drought, can sometimes be approxi-
mately estimated. In Kansas and Nebraska, in 1900,
the value of one rain, lasting twenty-four hours,
in saving the com erop was put at over $80,000,000.
In Australia, the wheat erop, as has been shown by
Wills, is so closely related to rainfall that the ratio
of wheat in bushels per acre and the annual rainfall
in inches has been made out to be a remarkably
320
CLIMATE
definite one. Similarly, the number of sheep per
square mile in Australia and in Argentina depends
very closely upon the rainfall, as has also been shown
by Wills. Unseasonable weather, at any time of year,
disturbs trade, which is very closely adjusted to the
normal weather conditions that may reasonably be
expected at any given time. Strikes have come to
an end because of the approach of cold weather, and
the prospects of suffering among the strikers; and
strikes have continued during great heat because of
the desire of the men to remain idle at such times.
Certain atmospheric conditions seem to be more
favourable than others to spontaneous combustion.
A dense London fog causes a heavy money loss in
the extra expense for gas and electric light, and in
the delay and damage to shipping. It has been esti-
mated that the cost of the gas bumed during one day
of an ordinary London fog approximates $15,000.
In New York city, the coming of a summer afternoon
thunder storm is reported by watchmen to the electric-
light power-houses, where the dynamos are set going
at full speed in order to supply the sudden demand
for extra light. In England, a good deal of business
is done by insurance companies in indemnifying
cricket clubs against loss in case an important game
happens to be interfered with by rain. So many
claims have arisen for the insurance money that it
has become customary in such cases to stipulate what
amount of rain shall fall in order that the claim shall
be paid. Insurance against damage by tornadoes,
LIFE OF MAN IN TEMPERATE ZONES 321
lightning, hail, etc., illustr&tes the efforts of man to
guard against loss due to hostile features of his
weather and climate. The danger from tomadoes
on the western plains and prairies of the United
States has led to the building of underground “ dug-
outs,” or tornado cellars, which are somewhat akin to
the underground winter dwellings of some of the
natives tribes of northem Siberia, built as a protection
against winter storms. Such illustrations might be
multiplied indefinitely.
CHAPTER X
THE LIFE OF MAN IN THE POLAR ZONES
General: A Minimum of Life—Culture—Subdivisions of the
Arctic Zone—Characteristics of the Tundra—The Reindeer—
Population and Occupations—Dwellings-^-Food and Clothing
—Iceland—The Polar Ice Cap: The Eskimo—Dwellings—
Food and Clothing—Travel and Transportation—Occupations
and Arts—Customs—Deserts of Sand and Deserts of Snow.
General: A Minimum of Life. The conditions of
life are necessarily very specialised under the peculiar
climatic features which are met with in the polar
zones. A “ monotony of cold ” replaces the “ mono-
tony of heat ” of the tropics, and instead of the spur
of the temperate zone seasons there is the depressing,
long, polar night. There is a minimum of life, but
life is more abundant in the north polar than the
south polar zone, and our knowledge is confined
chiefly to the former area. Plants are few and
lowly. In the farther north, only a few mosses and
lichens are found. Land animals which depend upon
plant food must therefore likewise be few in number.
Farming and cattle-raising cease. The reindeer,
which manages to find sufficiënt food in the lowly
Arctic vegetation, is the mainstay of many of the
-
323
LIFE OF MAN IN POLAR ZONES
323
Arctic natives. But the reindeer must wander far
and wide in search of their moss. And many rein-
deer are needed to provide sustenance for one man.
Population is small and scattered. There are no
permanent settlements at all within the Antarctic
circle. And the few scattering islands in the im-
mediately surrounding, vast ocean area of the south
temperate zone are likewise uninhabited, except tem-
porarily by shipwrecked seamen or, lately, by mem-
bers of scientific parties. In the Arctic area human
settlements are fairly well scattered over a consider-
able range near the margins of the zone, but with
increasing latitude man is more and more rarely seen,
and finally he disappears entirely. There will never
be permanent human settlements at the poles. Life
is hard; a constant struggle for existence. Man seeks
his food by the chase on land, but chiefly in the sea.
Hardly a tenth of Greenland’s population could live
there without food from the sea. It has been well
said that with every degree of higher latitude man is
more forced to obtain his food supply from the sea.
He lives along, or near, the sea coast. The interior
lands, away from the sea, are deserted. Gales, and
snow, and cold, cause many deaths on land, and also
at sea, especially during fishing expeditions. It has
been estimated that about one twenty-fifth of the
population of Iceland perishes through being lost in
snowstorms, by freezing, or by drowning. In the
Faroe Islands about 8%, and in Greenland 7% of
the deaths have been reported as due to drowning
324
CLIMATE
accidents of one sort or another. Rink has reported
of Greenland that most of the deaths occur at sea-
sons of most profitable sealing operations. Such dif-
ficult conditions of securing food make famine a likely
occurrence. If a successful hunting or sealing ex-
pedition follows a time of famine, the natives are
wont to indulge in the most revolting gorges. The
polar limit of permanent human settlements is be-
lieved by Bessels to be fixed, not by the decreasing
temperature, but by the increase in the length of the
night, which shortens the time during which man can
lay up food by hunting and fishing, to last him
through the polar night. The chase after land ani-
mals has helped to drive the latter farther and
farther north.
Culture. Under such adverse conditions it is not
hard to see that progress towards a higher culture is
not a reasonable expectation. There is no time in
which man may seek to develop and satisfy his higher
needs. Much truth is contained in Quyot’s some-
what picturesque statement: “ The man of the polar
regions is the beggar overwhelmed with suffering,
who, too happy if he but gain his daily bread, has no
leisure to think of anything more exalted.” Thus
the inhabitants of the north polar zone have not played
an important róle in the history of human progress.
A sparse population, not far advanced in culture or
in social relations, is inevitable under polar conditions
of climate. Yet the courage of the Eskimo in brav-
ing a raging sea in his kayak, or in facing a polar
LIFE OF MAN IN POLAR ZONES
325
bear; the docility, industry, good nature, and other
attractive qualities of these people, which have been
described by more than one Arctic explorer; the in-
telligence and the patience with which they have
overcome the disadyantages of their environment;
the contributions made by Iceland to the world’s
literature—these and other similar considerations
make us pause bef ore passing too hasty a judgment.
Polar cold has not produced a distinct type of polar
man, but the general effect of the polar climate in
eliminating cattle-raising and agriculture—except to
a very limited extent, and in a few favoured localities
—from the list of human occupations; in tuming man
to the sea for his food; in magnifying the importance
of animal products, especially bones, in the produc-
tion of domestic utensils and weapons, is more or less
familiar among all Arctic tribes. There is no steady,
profitable occupation in which large numbers of men
may be regularly employed at good wages. Broad,
general analogies have been traced between the
northem Eskimos and the Fuegians of far southem
South America.
Subdixnsions of the Arctic Zone. For the purpose
of this consideration the north polar zone may con-
veniently be subdivided into (1) the lowlands of the
tundra, where the summer sun melts off the snow and
thaws out the upper few inches, or possibly few feet,
of the frozen ground, and (2) the permanently ice-
and snow-covered higher land, where the heat of the
summer does not remove the icy cover, and where
326
CLIMATE
man, so far as he inhabits those districts at all, must
live along the margins of the ice-cap, near the sea. In
whichever portion of the Arctic man is found, his
general mode of life, his occupations, his dwellings,
food, clothing, arts, and so on, are rigidly controlled
by climate.
Characteristics of the Tundra. The low-lying
frozen desert along the shores of the Arctic Ocean
is known as the tundra. “ Barren Lands ” is the
name by which it goes in Canada. Through beits of
lowly, scattering trees, these lowlands gradually
merge on the south into the northernmost forests of
the temperate zone. To the north are etemal snow
and ice. Over the treeless tundra the soil is per-
manently frozen to a great depth, but the upper part
of the surface thaws out sufficiently during the sum-
mer to produce a great plain, more or less swampy,
which may become dry in places in midsummer.
Scattered dumps of trees, chiefly along the water-
courses, relieve the monotony of the dead-level here
and there, and during the summer the tundra is cov-
ered for a few weeks with lowly lichens, mosses, and
fems, or even with the green leaves of stunted berry-
bushes, whose roots are all near the surface. At this
season, also, brilliant flowers, insects, and birds give
life and charm to the scene. With their polar char-
acteristic of an extraordinarily rapid growth, under
the summer sun, the plants of the tundra awaken as
if hy magie. The summer is in striking contrast
with the winter, when these great plains are frozen
LIFE OF MAN IN POLAR ZONES
327
solid, rivers and all, under a broad sheet of snow.
Joumeys by dog or reindeer sledge, or on skis, can
be made in any direction, regardless of the presence
of water or land beneath the snows, the routes to be
followed being accurately indicated by means of
landmarks. Thus in the Yukon country of Alaska,
as long as the rivers remain frozen, dog-sledges are
used in the interior to carry the mails and other
freight. This is much more expensive than the sum-
mer transportation by boat. When the snow is in
good condition, the natives can travel at the rate of
fourteen or fifteen miles an hour on skis. In spring
and early summer, when the upper portions of north-
ward flowing rivers melt, while the lower portions are
still frozen, floods are frequent over the lowlands. In
the transition season, when the rivers are not frozen
and the ground is not snow-covered, travel is usually
difficult or impossible. In the month of October, in
northem Russia, for example, the govemment mail
service is discontinued, labour contracts are off, and
the keepers of stages are freed from their usual obli-
gations. The fact that her northem ports are ice-
bound in winter is a serious handicap to Russia. This
was one of the principal reasons for her desire to se-
cure an ice-free port on the Pacific, Vladivostock, the
original terminus of the trans-Siberian Railroad,
being also ice-bound in winter. This led to the ac-
quisition of Port Arthur, and eventually to the war
with Japan. An open port would be an immense
gain for Russia, which has heen much handicapped
328
CLIMATE
in training her sailors by the freezing of the Baltic
harbours in winter.
The Reindeer. The reindeer in Eurasia and the
caribou in North America are the most important ani-
mals of the tundra. They feed on lichens and mosses,
or stunted shrubs. The reindeer is wonderfully
adapted to the natural conditions under which it
lives. With wide hoofs, well-fitted for travel over
the snow, it moves very swiftly. Able to endure
great cold, it scrapes through the snow in winter to
find the reindeer moss on which it feeds. It migrates
northward in summer and southward to the forests
in winter, in search of food. The reindeer has been
partly trained as a domestic animal by the natives of
the tundra. To them, the reindeer is of the utmost
importance: a man’s wealth is rated according to the
number of these animals in his possession, and their
loss, by reason of famine or disease, usually means
that the owners are reduced to poverty. The rein-
deer supplies milk and flesh for food; it is an excel-
lent draught animal; its skin, and sinews, and bones
furnish material for clothing, tents, and utensils and
weapons of all sorts.
Population and Occupation. The scattered nom-
adic tribes of the tundra, a semi-pastoral and semi-
hunting population, wander about with their reindeer
over the vast stretches of the tundra, stopping wher-
ever the animals find food; having no settled abode;
making little progress in the cultivation of the higher
arts. Population is inevitably sparse, and will so re-
LIFE OF MAN IN POLAR ZONES
329
main. The Lapps; the Eskimos, along the borders
of the Arctic Ocean; the Samoyads, Yakuts, Ostyaks,
Tunguses—all have a common mode of life. Hunt-
ers and fishermen by force of circumstances, they
can never become farmers. In winter» they hunt for
small fur-bearing animals or for larger game along
the borders of the southem forests. In summer, they
fish in the rivers or along the shores, storing away
food for the winter. They are always on the move.
Some of the tribes live along the forest borders in
the winter, for the saké of the shelter there provided.
The men procure food and make the needed imple-
ments and weapons. The women prepare the food
and clothing; watch the reindeer; collect berries in
summer; dry the fish; and even take charge, among
the Samoyads and Ostyaks, for example, of setting
up and taking down the tents, in order that the men
may have more time for the chase. The ill, the weak,
and the aged receive little attention.
Dwellings. The inhabitants of the tundra protect
themselves against the inclemencies of the weather in
summer by means of portable tents made of skins or
bark, supported by poles. In winter, the structure
is often more substantial, having more coverings or
being made of turf, or, in the case of some of the
Lapps, even of snow. Where timber is scarce, far
from forests, the Samoyads and Ostyaks consider
their tent-poles very valuable property, and carry
them along with the greatest care. The tribes who
live nearer the forests do not take the trouble to
330
CLIMATE
transport the tent-poles when they move. In the
far north, away from the forests, driftwood is an im-
portant source of lumber supply. The furnishings
are very simple and easily moved when tents are
struck. Furs and skins are the principal articles of
trade among the inhabitants of the tundra.
Food and Clothing. The natural food is obtained
chiefly from the reindeer and other land animals and
wild fowl, whose flesh is often eaten raw. Reindeer
milk, fish, berries, and a little other vegetable food,
are occasionally added to the monotonous and unat-
tractive diet list, as is fresh or dried blood. Trade
with the neighbouring, more highly civilised people
on the south gives tea and coffee, tobacco, and other
articles of food. In northem Alaska caribou, bear,
salmon, rabbits, grouse, and ptarmigan make up the
principal food of the natives.
The clothing of the tundra tribes shows climatic
control in the character and in the simplicity of the
materials used. Furs and skins are universally em-
ployed. The Samoyads, Tunguses, and others often
ornament their furs with bands of brightly coloured
stuffs, when these can be secured. Mittens, caps,
and boots of fur are essential for protection against
the winter cold. Implements of the chase and do-
mestic utensils are ingeniously made of wood, when
available, or of the skin, sinews, and bones of the
reindeer. Needles and spoons are commonly made
of bone; for thread, gut is used. It is worth noting
that the fossil elephants found frozen in the gravelly
LIFE OF MAN IN POLAR ZONES
331
river banks of the Siberian tundras have, ages later,
furnished ivory for the Chinese to fashion into their
delicate and beautiful carvings.
Iceland. Although outside of the Arctic circle,
Iceland is within the polar zone according to Supan’s
classification. Its climatic conditions are, however,
peculiar on account of its being an island, exposed to
the tempering influence of the warm Atlantic waters.
Favoured as it is, the climate is unsuitable for grain,
breadstuffs and other articles of food being imported.
Sheep, cattle, and horses are raised, and fish, feathers,
skins, horses, wool, tallow, and other local products
are exported. The summer is the natural time for
travel, by land or water, and for this reason, the
judicial assemblies have in the past been held in that
season. The natives of Iceland, although much
handicapped, have played their part in the world’s
progress, as enterprising sailors and discoverers, and
have developed a literature.
The Polar Ice-Cap: The Eskimo. The polar peo-
ple par excellence, the Eskimos, live characteristically
on the margins of the Arctic ice-cap, beyond the
tundra, along the shores of the Arctic seas. The
Eskimo, in common with other Arctic natives, must
secure his food almost wholly from the sea. When
he needs to travel to any distance for food, he moves
his dwelling. He is necessarily nomadic in his
habits. His existence is in many ways not unlike
that of the hunting tribes of the equatorial forests.
Dwellings. The rode but substantial dome-
832
CLIMATE
shaped ice or snow hut (igloo) of the Eskimo fum-
ishes one of the most striking illustrations of the
climatic control over human dwellings. Built low,
and entered by a low passageway, the doorway may
be closed with a block of ice or snow, and thus cold
and drifting snow and prowling animals are kept
out. The igloo» are fumished with the simplest
utensils—a “ stove ” or lamp to give heat and light,
with blubber for fuel and oil, and dried moss for a
wiek; a dish for melting ice for drinking purposes, and
for heating the seal or other meat. A clear sheet of
ice, made air-tight by having water poured over it, not
infrequently does duty as a window as effectively as
a pane of glass, and is even preferred to glass. These
snow huts are carefully built, as pointed out by
Woeikof, not of freshly-fallen snow, but of snow well-
compacted by successive storms and winds. The
snow becomes dense by this means, and not by being
successively melted and frozen, as in a névé. In
the drier parts of Greenland, simple earth or stone
houses are also used, and in the larger towns wooden
houses, built of imported lumber, are the ordinary
residences of the inhabitants. The snow igloo is the
common type of the more permanent winter dwell-
ing. In summer, when these huts may be damp
with melting snow, the nomadic Eskimo travels with
tents made of skins, sewed with animal sinews or
strips of leather, and set up with tusks or bones.
Settlements, established during wanderings in search
of good hunting and fishing grounds, may fre-
LIFE OF MAN IN POLAR ZONEB
333
quently be occupied and abandoned several times, and
the ruins of abandoned settlements north of the
present limits of human habitations may probably
often be thus explained. Even in winter, if the
food supply gives out, changes of residence are not
uncommon.
Food and Clothing. The clothing of the Eskimo
is made of skins of the reindeer, seal, or bëar, or óf
birds, wom almost in their natural state. As a pro-
tection against the cold, the face is often smeared
with fat. Food consists chiefly, or wholly, of heat-
producing materials, such as bear or seal meat, and
blubber from seal, walrus, or whale, eaten raw or
barely heated through. Any surplus food is usually
well preserved by the cold.
Travel and Transportation. The need of quick
travel, over great distances on land, in search of food,
makes the dog-sledge an indispensable possession of
the Eskimo. The dog, living on animal food, can
travel farther north-than the reindeer, and is the typi-
cal polar draught-animal beyond the reindeer coun-
try. The dog-sledge has spread the Eskimo far and
wide over the Arctic zone. Conditions are not always
equally favourable for sledging. Sometimes the
runners are covered with ice to make them smoother
and to prevent their sinking into the snow. In Lab-
rador, the winter storms which sweep off the loose
snow and leave the surface hard and smooth are wel-
comed as giving the best conditions for sledging.
Occupations and Arts. Hunting and fishing,
334
CLIMATE
training the dogs, and making kayaka, sledges, weap-
ons, and utensils are the chief occupations of the men,
while the women make the clothing and chew the
skins to soften them. The Eskimo displays the
greatest mechanical skill and ingenuity in fashioning
all his tools and utensils. As trees do not grow in his
country, wood is so scarce that every bit of it is used,
small pieces even being bound together with leathem
thongs to make the handles of knives and harpoons,
and the like. Every piece of driftwood is a precious
possession, more valuable often than iron. Drift-
wood plays an important part in the history and laws
of Iceland, and Nansen says that the driftwood “ car-
ried down by the polar current along the east coast of
Greenland and up the west coast is . . . essential
to the existence of the Greenland Eskimo.” Wood
and iron are used instead of bone and skins. The
utensils of Arctic natives show at once whether or not
they have had access to supplies of driftwood. It has
been well said that where driftwood is found undis-
turbed this is good evidence that there are no Eski-
mos in the vicinity. The distribution of man thus
depends largely on the course taken by the driftwood.
The skill of the Eskimo is well shown in his construc-
tion of the kayak, made of skins sewn together and
stretched over a framework, a marvel of lightness, in-
destructibility, and portability, easily righted if over-
turned, which fits the boatman as if he and his boat
were one. Needles and thimbles are made of bone;
animal fibres are used for thread; narwhal tusks serve
LIFE OF MAN IN POLAR ZONES
as tent-pegs. The Eskimo can make or mend any-
thing that he uses. Nothing is wasted. The Eski-
mos are naturally expert sailors, because of their life
on the sea. In towing their catches to land, they
make use of inflated bladders or skins.
Customs. The lack of water, and the cold, com-
bine to make personal cleanliness difficult, and the
people are characteristically very dirty. The winter,
when the Eskimos are living in their more permanent
huts, is the time for social visiting, and then they
travel for miles in the family sledges to visit their
friends. Marriages take place at an early age,
especially among the women, and the return of the
sun after the long winter has a stimulating effect on
the animal passions which leads to sexual excesses of
all kinds.1
-
Deserts of Sand and Deserts of Snow. The hot
deserts of sand near the equator and the frozen des-
erts of snow near the pole are singularly alike in many
ways in relation to man. Both alike repel him. Both
are largely or wholly destitute of vegetation, of wood,
and of water. The grey or yellow desolate waste of
the sand desert is matched by the monotonous white
surface of the snow desert. There are no opportuni-
ties for accumulating wealth in either. Travel is dif-
ficult in both. In one, the camel is the typical beast
of burden; in the other, the reindeer and the dog are
man’s most useful possessions. The monotonous
1Dr. P. A. Cook: “ Some Physiological Effects of Arctic Cold,
Darkness and Light,” Med. Ree., June 12, 1897, pp. 833-836.
336
CLIMATE
heat and glare and silence of the sand desert find their
counterpart in the cold and glare and silence of the
snow desert. The air is generally clear in both, ex-
cept for the dust over the sand desert and the ice-
needles in the air of the snow desert. In both deserts
man in very limited in his food supply; in the Sahara,
the date, and in Greenland, the seal, are typical staple
articles of diet. The aridity in one, the cold in the
other, are man’s great enemies. The inhabitants of
both deserts are nomadic. Settlements of some per-
manency are found in oases or along the edges of the
sand desert where there is water; similarly, the natives
of the far north live along the edges of the ice
desert, where they can best find their food. The
sand deserts are deserts because they are and. The
snow deserts are deserts because they are cold.
Denudation of exposed rocks in both types of desert
is largely due to the action of wind, for running
water is seldom found. The dust of disintegration
is carried away by the winds, and sand-blasting has
been reported of the antarctic desert as well as of
the Sahara. The polar deserts are perhaps on the
whole better suited to life than the sand deserts, for
the former do supply water from melted snow and
ice, and over the tundra portion of the frozen desert
there is an abundance of water in the rivers in sum-
mer, with moss, berries, and other vegetation, as well
as animal food. Man has, however, a harder strug-
gle to protect himself against the cold than against
the heat. for he needs more clothing, and better shel-
LIFE OF MAN IN POLAR ZONES
337
ter, and fire. In both deserts life is isolated and
primitive. The sand desert is crossed by caravans
and trade routes between the more populous lands on
either side, and the people of these deserts have more
contact with civilisation than do most of the natives
of the far north.
CHAPTER XI
CHANGES OP CLIMATE
Popular Belief in Climatic Change—Evidence of Climatic Changes
Within Historie Times—What Meteorological Records Show
—Why the Popular Belief in Climatic Changes is Untrust-
worthy—Value of Evidence Concerning Changes of Climate—
Periodic OBcillations of Climate: The Sun-spot Period—Brück-
ner's 35-Year Cycle—Climatic Cycles of Longer Period—
Geological Changes in Climate—Condusion.
Popular Belief in Climatic Change. Belief in a
change in the climate of one’s place of residence,
within a few generations, and even within the mem-
ory of living men, is widespread. It is confined to
no special region or people. It finds support among
the most intelligent as well as among the uneducated.
Here it may be the view that the climate is growing
milder; there, that the winters are becoming more
severe; here, that there is increasing aridity; there,
that the rainfall is greater. Whenever a season
attracts attention because of weather conditions
which seem in any way unusual, this ‘belief is
strengthened. This popular impression has often
found support in the facts of distribution, or the
dates of flowering, or ripening, of certain cereals or
fruits. It is asserted that because grapes, or com,
338
CHANGES OF CLIMATE
339
or olives, for example, are now no longer grown in
parts of Europe where their cultivation was once
an important occupation, we must conclude that
the climate has changed from a favourable to an
unfavourable one.
Evidences of Climatic Changes within Historie
Times. Evidence is constantly being brought for-
ward of apparent climatic variations of greater or
less amount which are now going on. Such reports,
largely those of travellers or explorers in little-known
regions, are usually based on fluctuations in the ex-
tent of inland lakes; on the discovery of abandoned
dwelling sites, the ruins of aqueducts and irrigating
canals, and the like. Thus we have accounts of a
gradual desiccation which seems to have been going
on over a large region in central Asia, during histori-
cal times. In eastern Turkestan the lakes have been
reported as drying up, Lake Balkash falling one
metre in about fifteen years, and Lake Alakul gradu-
ally becoming a salt deposit. In his work on Turkes-
tan, Muschketoff gives numerous examples of
Progressive desiccation, and Rossikoff speaks of the
drying up of the lakes on the northem side of the
Caucasus. The same thing is reported of lakes in
the Pamir. Prince Kropotkin believes that the desic-
cation of central Asia in the past drove the inhabit-
ants out onto the lowlands, producing a migration
of the lowland peoples and thus bringing on the in-
vasions of Europe during the first centuries of our
era. In his recent work on the basin of eastern
340
CLIMATE
Persia, Transcaspia, and Turkestan, Huntington be-
lieves that, so far as it can be made out, the history
of these countries indicate* a gradual desiccation from
early historical times down to the present day. His
study of climatic changes in that region is one of the
most thorough ever made, for the evidences of archae-
ology, of tradition, of history, and of physiography
have been carefully matched and found to accord in a
very striking manner. Evidence has heen found of
the abandonment of successive village sites as the in-
habitants moved farther upstream in search of more
water, and patches of dead jungle show that vegeta-
tion once flourished where aridity now renders plant
growth impossible.
In northem Africa, certain ancient historical re-
cords have been taken by different writers to indicate
a general decrease of rainfall during the last 8000
years or more, the remains of cities and the rains of
irrigating works pointing to a larger population and
a greater water supply formerly than at present.
The presence of certain animals, now no longer found
there, is implied by ancient records, and from this
fact also, a change of climate is inferred. In his Cross-
ing of the Sahara between Algeria and the Niger,
Gautier found evidence of a former large population.
A gradual desiccation of the region is, therefore, be-
lieved to have taken place, but to-day the equatorial
rain-belt seems to be again advancing farther north,
giving an increased rainfall. Gautier divides the
history here into three periods: (1) dense population;
CHANGES OF CLIMATE
341
(2) aridity; and (3) the present change to steppe
character.
Farther south, several lakes have been reported as
decreasing in size, e. g., Chad, Ngami, and Victoria;
and wells and springs as running dry. In the Lake
Chad district, Chevalier reports the discovery of
vegetable and animal remains which indicate an in-
vasion of the Sudan by a Saharan climate. Neolithic
relics indicate the former presence there of prosper-
ous communities. Again, to note another instance,
it is often held that a steady decrease in rainfall has
taken place over Greece, Syria, and other eastern
Mediterranean lands, resulting in a gradual and in-
evitable deterioration and decay of their people.
These examples might be multiplied, for reports of
climatic changes of one kind or another are numerous
from many parts of the globe.
What.Meteorological Records Show. As concerns
the popular impression regarding change of climate,
it is clear at the start that no definite answer can be
given on the basis of tradition, or of general impres-
sion, or even of the memory of the “oldest inhabi-
tant.” Human memories are very untrustworthy,
and there are many reasons for their being particu-
larly untrustworthy in matters of this kind. The only
answer of real value must be based on what the in-
strumental records of temperature, and of rain and
snowfall show. Accurate instruments, properly ex-
posed and carefully read, do not lie; do not forget;
are not prejudiced. When such instrumental records,
342
CLIMATE
scattered though they are, and difficult as it is to
draw general condusions from them, are carefully
examined, from the time when they were first kept,
which in a few cases goes back about one hundred and
fifty years, there is found no evidence of any progres- ‘
sive change in temperature, or in the amount of rain
and snow. Apparent signs of a permanent increase
or decrease in one or another element have been fairly
easy to explain as due to the method of exposing the
thermometer, or of setting up the rain-gauge. Little
care was formerly taken in the construction and loca-
tion of meteorological instruments. They were usu-
ally in cities, and as these cities grew, the temperature
of the air was somewhat affected. The rain-gauges
were poorly exposed on roofs or in court-yards. The
building of a fence or a wall near the thermometer,
or the growth of a tree over a rain-gauge, is
enough, in many cases, to explain any observed
change in the mean temperature or rainfall. Even
when the most accurate instrumental records are
available, care must be taken to interpret them cor-
rectly. Thus, if a rainfall or snowfall record of sev-
eral years at some station indicates an apparent
increase or decrease in the amount of predpitation,
it does not necessarily follow that this means a per-
manent, Progressive change in climate, which is to
continue indefinitely. It may mean simply that there
have been a few years of somewhat more predpita-
tion, and that a period of somewhat less precipitation
is to follow.
CHANGES OF CLIMATE
343
For the United States, Schott, some twenty years
ago, made a careful study of all the older records of
temperature and rainfall, including snow, from
Maine to California, and found nothing which led to
the view of a Progressive change in any one direc-
tion. There was evidence of slight variations of
temperature, occurring with the same characteristics
and with considerable uniformity over large areas.
These variations have the characteristics of irregular
waves, representing slightly warmer and slightly
cooler periods, but during the fluctuations the tem-
perature differed by only a degree or two on one side
or the other of the mean. Obviously, this is too
slight a range to be of any general or practical inter-
est, and in any case, these oscillations give no evidence
of a continuous change toward a warmer or a cooler
climate. Schott found that these waves of higher
and lower temperature followed one another at inter-
vals of about twenty-two years on the Atlantic coast.
In the interior, the intervals were about seven years.
The records of the closing of rivers to navigation, the
Hudson, for example, show no permanent change in
the dates for the last hundred years or so.
It has been well pointed out that if a list were care-
fully compiled of heavy snowstorms, of droughts, of
floods, of severe cold, of mild winters, of heavy rains,
and of other similar meteorological phenomena, for
one of the early-settled sections of the United States,
beginning with the date of the first white settlements
and extending down to the present day, we should
344
CLIMATE
have the following situation: Dividing this list into
halves, each division containing an equal number of
years, it would be found, speaking in general terms,
that for every mild winter in the first half, there would
be a mild winter in the second; for every long-
continued drought in the first division, there would
be a similar drought in the second; for every “old-
fashioned ” winter in the first group, there would be
an “ old-fashioned ” winter in the second. And so
on, through the list. In other words, weather and
climate have not changed from the time of the land-
ing of the earliest pilgrims on the inhospitable shores
of New England down to the present day.
Why the Popular Belief in Climatic Changes. is
Untrustworthy. Why is the popular belief in a
change of climate so widespread and so firmly fixed,
when instrumental records all go to show that this
belief is erroneous? It is not easy to answer this
question satisfactorily, but several possible explana-
tions may be given. The trouble arises chiefly from
the fact that we place absolute trust in our memories,
and attempt to judge such subtle things as climatic
changes on the basis of these memories, which are at
best short, defective, and in the highest degree un-
trustworthy. We are likely to exaggerate past
events; to remember a few exceptional seasons which,
for one reason or another, made a deep impression
on us, and we thus very much overrate some special
event. To make use of an illustration given by an-
other, individual severe winters which, as they occur,
CHANGES OF CLIMATE
345
may be some years apart, seem, when looked back
upon from a distance of several years later, to have
been close together. It is much as in the case of the
telegraph poles along a railroad track. When we
are near the individual poles, they seem fairly far
apart, but when we look down the track, the poles
seem to stand close together. The difference in the
impressions made upon youthful and adult minds
may account for part of this misconception regard-
ing changes of climate. To a youthful mind a heavy
snowstorm is a memorahle thing. It makes a deep
impression, which lasts long and which, in later years,
when snowstorms are just as heavy, seems to dwarf
the recent storms in comparison with the older. The
same is true regarding heavy rains, or floods, or
droughts.
Changes of residence may account for some of the
prevailing ideas about climate. One who was
brought up as a child in the country, where snow
drifts deep and where roads are not quickly broken
out, and who later removes to a city, where the tem-
peratures are slightly higher, where the houses are
warmer, and where the snow is quickly removed from
the streets, naturally thinks that the winters are
milder and less snowy than when he was a boy.
Similarly, a change of residence from a hill to a val-
ley, or vice versa, or from the coast to the interior,
may easily give the impression of a changing climate.
Even in cases where individuals have kept a record of
thermometer readings during a long series of years,
346
CLIMATE
and are sure that the temperatures are not as low
or as high as they used to be, or who are convinced
that the rainfall is lighter or heavier than it was some
years before, the chances are that the location of the
thermometer, or the exposure of the rain gauge, has
been changed sufBciently to account for any observed
difference in the readings.
Value of Evidence Conceming Change» of CU-
mate. The body of facts which has been adduced as
evidence of Progressive changes of climate within his-
torical times is not yet sufliciently large and complete
to warrant any general correlation and study of these
facts as a whole, especially from the point of view of
possible causation. But there are certain considera-
tions which should be bome in mind in dealing with
this evidence, certain corrections, so to speak, which
should be made for possible Controls other than cli-
matic, before condusions are reached in favour of
climatic changes. In the first place, it has been noted
above that changes in the distribution of certain
fruits and cereals, and in the dates of the harvest,
have often been accepted as undoubted evidence of
changes in climate. Such a conclusion is by no means
inevitable, for it can easily be shown that many
changes in the districts of cultivation of various
crops naturally result from the fact that grapes, or
com, or olives, are in time found to be more profitably
grown, or more easily prepared for market in another
locality. Thus the area covered by vineyards in
northem Europe has been very much restricted in the
CHANGES OF CLIMATE
347
last few hundred years, because grapes can be raised
better and cheaper farther south. Cultivation in one
district is abandoned when it is more profitable to im-
port the product from another. It is easy, but not
right, to conclude that the climate of the districts first
used has changed. Wheat was formerly more gen-
erally cultivated far north in the British Isles than is
the case at present, because it was profitable. Later,
after a readjustment of the taxes on breadstuffs, it
was no longer profitable to grow cereals in that
region, and the area thus cultivated diminished.
Changes in the facility, or in the cost, of importation
of certain articles of food from a distance are speedily
followed by changes in the districts over which these
same crops are grown. Similarly, the introduction of
some new plant, better suited to the local soil and
climate, will result in the replacement of the older pro-
duct by the newer. In France, Angot has made a
careful compilation of the dates of the vintage from
the fourteenth century down to the present time, and
finds no support for the view so commonly held there
that the climate has changed for the worse. The dates
of the vintage do, however, indicate some oscillation
of the climatic elements. In the period 1775-1875,
the average date of the grape harvest in Aubonne was
about ten days earlier than during the preceding cen-
tury, but three days later than during the second
century preceding. At the present time, the average
date of the grape harvest in Aubonne is exactly the
same as at the close of the sixteenth century. After
348
CLIMATE
a careful study of the conditions of the date tree, from
the fourth century b. c., Eginitis concludes that the
climate of the eastern portion of the Mediterranean
basin has not changed appreciably during twenty-
three centuries. In China, a comparison of the
ancient and present-day conditions of cultivation, of
silk production, and of bird migrations, has led Biot
to a similar conclusion. In some cases, the reported
cultivation of cereals, or other soil products, in cer-
tain climates at present unfavourable has been shown
to be purely a myth; as in the case of a supposed
extended cereal cultivation in Iceland in former
times.
Secondly, a good many of the reports by explorers
from little-known regions are contradictory. Thus
Lake Aral, which was diminishing in area for many
years, is recently reported by Berg as increasing.
Lake Balkash, which was rapidly drying up, has also
begun to fill again. Partly submerged trees are
noted as having been seen by Berg, who in June,
1902, found the lake waters quite fresh. As the lake
has no outlet, this is an interesting fact. In Africa,
Lake Victoria, which, it was generally agreed, was
sinking in the period 1878-1892, has since shown a
tendency to rise. Lake Rukwa, east of Tanganyika,
has risen within the last few years. Reports that the
Sea of Azov is drying up have been explained as due
to a silting up of the lake. Lake Chad is very prob-
ably subject to oscillations, sometimes spreading be-
yond its usual limits as the result of several years of
CHANGES OF CLIMATE
349
-
heavy rainfall. Such diverse reports show the need
of caution in jumping at condusions of climatic
change. An increased use of water for irrigation
may cause the level of water in a lake to fall, as has
been the case to some extent in Great Salt Lake.
Periodic oscillations, giving higher and then lower
water, do not indicate Progressive change in one di-
rection. Many writers have thus seen a law in what
was really a chance coincidence. Partsch believes
that the ancient settlements on the interior lakes of
northern Africa show that these lakes contained no
more water formerly than they do now. Some have
claimed that the supposed desiccation of the climate
of northem Africa resulted from deforestation, but
no certain evidence exists of the presence or destruc-
tion of such forests, and if deforestation did take
place, no considerable change of climate could have
resulted.
Thirdly, where a Progressive desiccation seems to
have taken place, the question should be asked, Is less
rain actually falling, or have the inhabitants less
capacity, less energy, less ability, than formerly? Is
the change from a once cultivated area to a barren
expanse the result of decreasing rainfall, or of the
emigration of the former inhabitants to other lands?
The difference between a country formerly well irri-
gated and fertile, and a present-day, sandy, inhospit-
able waste may be the result of a former compulsion
of the people, by a strong goveming power, to till
the soil and to irrigate, while now, without that com-
350
CLIMATE
pulsion, no attempt is made to keep up the work.
The incapacity of the present inhabitants, or of their
rulers, is often responsible for effects which have been
interpreted as due to climatic change. Where irri-
gation is now being again resorted to in parts of the
districts about the Mediterranean which have been
reported to be drying up, there the former fruitful-
ness is returning. In Asia Minor, for example, the
rule of the Turk brought a change from a settled
and civilised to a semi-nomadic state of society; in-
dustries died out, the land to a great extent passed
out of cultivation; irrigation works were destroyed.
Recently the building of railroads and of roads has
been followed by a revival of industry and of agricul-
ture, and by the reclamation of waste land. In many
cases the reports of increasing dryness really concern
only the decrease in the water supply from rivers
and springs, and it is well known that a change in the
cultivation of the soil, or in the extent of the forests,
may bring about marked changes in the flow of
springs and rivers without any essential change in
the actual amount of rainfall. These conditions are
particularly likely to occur in regions where there is
no snow covering, and where the rain falls in a few
months only. In Tripoli, the Vicomte de Mathui-
sieulx finds that the Latin texts and monuments
seem to establish the fact that, so far as atmospheric
conditions and soil are concemed, everything is just
as it was in ancient times. The present condition of
the country is ascribed to the idleness of the Arabs,
CHANGES OF CLIMATE
351
who have allowed wells to become choked and vegeta-
tion to perish. “ In a -country so little favoured by
nature, the first requisite is a diligent and hard-work-
ing population. The Romans took several centuries
to make the land productive by damming rivers and
sinking wells in the wady beds.” In an arid region,
man has a hard task if he is to overcome the climatic
difficulties of his situation. Irrigation; the choiceof
suitable crops adapted to arid conditions; steady,
thoughtful work, are absolutely essential. To a large
extent, an intelligent man may thus overcome many
of the obstacles which nature has put in his way. On
the other hand, a region of deficiënt rainfall, once
thickly settled and prosperous, may readily become
an apparently hopeless desert, even without the in-
tervention of war and pestilence, if man allows the
climate to master him.
Lastly, a region whose normal rainfall is at best
barely sufficiënt for man’s needs, may be abandoned
by its inhabitants during a few years of deficiënt pre-
cipitation, and not again occupied even when, a few
years later, normal or excessive rainfall occurs. It
is a very striking fact that the districts from which
comes most of the evidence of changes of climate
within historical times are sub-tropical or sub-equa-
torial, i. e., they are in just those latitudes in which
a slightly greater or a slightly less migration of the
rain-bringing conditions easily produces a very con-
siderable increase or decrease in the annual rainfall.
It is apparent, on examining the evidence thus far
352
CLIMATE
at hand, that the fact of permanent, Progressive
changes in climate during historical times has not
yet been definitely established.
Periodic OscMatiom of Climate: Sunspot Period.
The discovery of a distinct eleven-year periodicity
in the magnetic phenomena of the earth, naturally
led to investigations of similar periods in meteorol-
ogy. Numerous and varied studies along this line,
extending back even into the seventeenth century,
but beginning actively about 1870, have been and
are still being prosecuted by a considerable number
of persons, and the literature on the subject has as-
sumed large proportions. The results, however,
have not been satisfactory. The problem is difficult
and obscure. It is natural to expect a relation of
this sort, and some relation certainly exists. But
the results have not come up to êxpectations. Fluctu-
ations in temperature and rainfall, occurring in an
eleven-year period, have been made out for certain
stations, but the variations are slight, and it is not
yet clear that they are sufficiently marked, uniform,
and persistent over large areas to make practical ap-
plication of the periodicity in forecasting possible.
In some cases, the relation to sunspot periodicity is
open to debate; in others, the results are
contradictory.
Koppen has brought forward evidence of a sunspot
period in the mean annual temperature, especially
in the tropics, the maximum temperatures coming
in the years of sunspot minima. The whole ampli-
CHANGES OF CLIMATE
353
tude of the variation in the mean annual tempera-
tures, from sunspot minimum to sunspot maximum,
is, however, only 1.3° in the tropics, and a little less
than 1° in the extra-tropics. There are, however,
long periods during which there appears to be no in-
fluence, or at least, an obscure one, and the relation
before 1816 seems to have been opposite to that since
then. More recently Nordmann (for the years
1870-1900) has continued Köppen’s investigation,
using the mean annual temperatures of certain tropi-
cal stations, and finds that the mean temperatures
run parallel with the sunspot curve, but that the
minimum temperatures occur with the sunspot
maxima (amplitude 0.7°). This seems to contradict
the fact that the sun is hotter at a time of maximum
sunspots. The latter difficulty has been explained
on the ground that the rainfall and cloudiness, both
of which are at a maximum with the sunspot curve,
lower the temperature, especially in the tropics. It
is obvious that the condition of this matter is rather
confusing just at the present time, and that the rela-
tion of sunspots and terrestrial temperatures is not
wholly clear. The sunspots themselves are probably
not the immediate or sole control. “ There seems
little doubt,” says Sir Norman Lockyer, “that we
must look to the study of the solar prominences, not
only as the primary factors in the magnetic and at-
mospheric changes in our sun, but as the instigators
of the terrestrial variations.” These investigations,
however interesting and important they may be to
354
CLIMATE
astronomers and physical meteorologists, are really
outside the field of climatology.
In 1872, Meldrum, then director of the meteoro-
logical observatory at Mauritius, first called attention
to a sunspot periodicity in rainfall and in the fre-
quency of tropical cyclones in the South Indian
Ocean. The latter are most numerous in years of
sunspot maxima, and decrease in frequency with the
approach of sunspot minima. Poëy later found a
similar relation in the case of the West Indian hurri-
canes. Meldrum's condusions regarding rainfall
were that, with few exceptions, there is more rain in
years of sunspot maxima. This is to he taken only
for means, and for a majority of stations, and is not
to be expected at all stations, or in every period. Hill
found it to be true of the Indian summer monsoon
rains that there seems to be an excess in the first half
of the cycle, after the sunspot maximum. The win-
ter rains of northem India, however, show the op-
posite relation; the minimum following, or coincid-
ing with, the sunspot maximum. Many studies
have been made of a possible relation between rain-
fall and the sunspot period, but the condusions are
not very definite, are sometimes contradictory, and do
not yet warrant any general, practical application
for purposes of forecasting the wet or dry character
of a coming year. Particular attention has been paid
to the sunspot cycle of rainfall in India, because of
the close relation between famines and the summer
monsoon rainfall in that country. In 1889, Blanford
CHANQES OF CLIMATE
355
admitted that the rainfall of India as a whole did not
give evidence of the sunspot cycle in the records of
the twenty-two years preceding. More recently, the
Lockyers have studied the variations of rainfall in
the region surrounding the Indian Ocean in relation
to solar changes in temperature. They find that
India has two pulses of rainfall, one near the maxi-
mum and the other near the minimum of the sunspot
period. The famines of the last fifty years have oc-
curred in the intervals between these two pulses, and
these writers believe that if as much had been known
in 1886 as is now known, the probability of famines
at all the subsequent dates might have been foreseen.
Relations between the sunspot period and various
meteorological phenomena other than temperature,
rainfall, and tropical cyclones have been made the
subject of numerous investigations, but, on the whole,
the results are still too uncertain to be of any but a
theoretical value. Some promising condusions
seem, however, to have been reached in regard to
pressure variations, and their control over other cli-
matic elements.
Brückner’s Thirty-five-Year Cycle. Of more im-
portance than the results thus far reached for the
sunspot period are those which clearly establish a
somewhat longer period of slight fluctuations or
oscillations of climate, known as the Brückner cycle,
after Professor Brückner, of Beme, who has made a
careful investigation of the whole subject of climatic
changes and finds evidence of a thirty-five-year
356
CLIMATE
periodicity in temperature and rainfall. Brückner
began with the long-period oscillations in the level
of the Caspian Sea. He then investigated the levels
of the rivers flowing into the Caspian, and next the
dates of the opening and closing of the rivers of the
Russian Empire, and finally extended his study over
a considerable part of the world, including data con-
cerning mean temperatures, rainfall, grape harvest,
severe winters, and the like. The dates of opening
and closing of Russian rivers go back in one case to
1559; the dates of rintage to the end of the fourteenth
century, and the records of severe winters to about
1000 a.d. In a cycle whose average length is thirty-
five years there comes a series of years which are
somewhat cooler and also more rainy, and then a
series of years which are somewhat warmer and drier.
Brückner has found that the price of grain averages
18 per cent. higher in the wetter lustrum than in the
drier. This thirty-five-year period is not to be
thought of as being a perfectly systematic recur-
rence, in exactly that term of years. The interval in
some cases is twenty years; in others, it is fifty. The
average interval between two cool and moist, or warm
and dry periods, is about thirty-five years. More-
over, not only the intervals, but the intensities of the
individual periods vary. The mean amplitude of the
temperature fluctuation, based on large numbers of
data, is a little less than 2°, which makes it greater
than that obtained by Koppen for the sunspot period,
and it is natural to expect it at a maximum in
CHANQES OF CLIMATE
357
Continental climates. The fluctuations in rainfall,
also, are more marked in interiors than on coasts.
The general mean amplitude is 12 per cent., or, ex-
cluding exceptional districts, 24 per cent. In western
Siberia more than twice as much rain may fall in wet
as in dry periods. Regions whose normal rainfall is
small are thus most affected. In years of minimum
precipitation they may become uninhabitable, and
the population may be forced to move away, perhaps
never returning, and allowing towns and irrigating
works to fall to decay. Slight fluctuations in rain-
fall are most critical in regions having a normal
precipitation barely sufficiënt for agriculture. The
extent of land cultivated, and the returns of agricul-
ture here fluctuate directly with the temporary in-
crease or decrease of rainfall. A supplementary
study of the newer rainfall observations for Russia
and for the United States, as well as for certain sta-
tions in central Europe and eastern Siberia, has given
Brückner satisfactory conflrmation of his earlier
condusions in the fact that he finds a decrease of rain-
fall over these districts as a whole, beginning about
the middle of the decade 1880-90. The time of the
“boom” in western Kansas and Nebraska, and in
eastern Colorado, in the decade 1880-90, followed
one of Brückner’s wet periods, and the collapse of
the “boom” came when the drier period advanced.
Farmers who went out onto the high plains in the
years of slightly greater rainfall preceding the boom,
and who lost all their Capital, and more too, in the
358
CLIMATE
vain attempt to raise their grain in the years which
followed, could with difficulty be convinced that the
climate of the plains had not permanently changed
for the worse. The impression left upon their
minds, and upon the mind of anyone who saw the
country later, was one of decreasing rainfall, unsuc-
cessful agriculture, and financial ruin. Within more
recent years, in this same region of Kansas, with a
somewhat increased rainfall during a wetter cycle,
but without any permanent change to a wetter cli-
mate, the intelligent choice of cereals better adapted
to the soil and climate, and the rational use of the
available water supply, have wrought a wonderful
change in the aspect and economie value of the state,
The following table shows the characters and dates
of Brückner’s periods:
Warm
Dry
Cold
Wet
1746-1755
1756-1770
i73i-i745
1736-1755
1791-1805
1781-1805
1756-1790
1771-1780
1821-1835
1826-1840
1806-1820
1806-1825
1851-1870
1856-1870
1836-1850
1841-1855
1871-1885
1871-1885
Interesting confirmation of Brückner’s thirty-five-
year period has been found by Richter in the varia-
tions of the Swiss glaciers, but as these glaciers differ
in length, they do not all advance and retreat at the
same time. The advance is seen during the cold and
damp periods. Supan has pointed out that the
Brückner periods appear to hold good in the south
polar regions. And Hann’s study of the monthly
and annual means of rainfall at Padua (1725-1900),
Klagenfurt (1818-1900), and Milan (1764-1900)
CHANGES OF CLIMATE
359
brings to light an altemation of wet and dry periods
in harmony with the thirty-five-year cycle. It should
be noted that Brückner has found certain districts
in which the phases and epochs of the climatic cycle
are exactly reversed. These exceptional districts are
almost altogether limited to marine climates. There
is thus a sort of compensation between oceans and
continents. The rainier periods on the continents
are accompanied by relatively low pressures, while
the pressures are high and the period dry over the
oceans, and vice versa. The cold and rainy periods
are also marked by a decrease in all pressure differ-
ences. It is obvious that changes in the general dis-
tribution of atmospheric pressures over extended
areas, of the great centres of high and low pressure,
are closely associated with fluctuations in tempera-
ture and rainfall. An oscillation of a few hundred
miles one way or another may mean the difference
between drought and plentiful rainfall over extended
areas. These changes in pressure distribution must
in some way be associated with changes in the gen-
eral circulation of the atmosphere, and these again
must depend upon some extemal controlling cause,
or causes. W. J. S. Lockyer has called attention to
the fact that there seems to be a periodicity of about
thirty-five years in solar activity, and that' this cor-
responds with the Brückner period. This longer
cycle, underlying the sunspot period, alters the time
of occurrence of the sunspot maxima in relation to
the preceding sunspot minima. He makes out
360
CLIMATE
three periods in solar activity, of between three and
four years, about eleven, and about thirty-five years,
respeetively. These are related as 1:3:9.
It is clear that the existence of a thirty-five-year
period will account for many of the views that have
been advanced in favour of a Progressive change of
climate. A succession of a few years wetter or drier
than the normal is likely to lead to the conclusion
that the change is permanent. Accurate observations,
extending over as many years as possible, and dis-
cussed without prejudice, are necessary before any
condusions are drawn. Observations for one sta-
tion during the wetter part of a cycle should not be
compared with observations for another station dur-
ing the drier part of the same, or of another cycle.
Climatic Cycles of Longer Period. There are
evidences of longer climatic cycles than eleven or
thirty-five years. Brückner calls attention to the
fact that sometimes two of his periods seem to merge
into one. Richter shows much the same thing for the
Alpine gladers. James Geikie, in Scotland, has
brought forward evidence of several climatic changes
in post-glacial times. Blytt, in Norway and Sweden,
finds some botanical evidence of four great climatic
waves since the last glacial period. Brögger esti-
mates that a mean annual temperature between 8°
and 4° higher than the present was found in the Chris-
tiana Fjord in post-glacial time. Lorié, in Holland,
finds confirmation of Blytt’s views. Gradmann, on
botanical evidence, believes in a warmer climate in
CHANGES OF CLIMATE
-
361
central Europe after the last ice age, and then a cooler
onet Clough concludes that a three-hundred-year
cycle exists in solar and terrestrial phenomena, the
thirty-six-year cycle being, as it were, superimposed
upon the longer one. Kingsmill reports a period-
icity of three hundred years in droughts and famines
in northem China. And so on. As yet, nothing
sufficiently definite to warrant discussion here has
been brought forward.
Geological Change» in Climate. Changes of cli-
mate in the geological past are known with absolute
certainty to have taken place; periods of glacial in-
vasions, as well as periods of more genial conditions.
The evidence and the causes of these changes have
been discussed and re-discussed, by writers almost
without number, and from all points of view.
Changes in the intensity of insolation; in the sun it-
self; in the conditions of the earth’s atmosphere; in
the astronomical relations of earth and sun; in the
distribution of land and water; in the position of
the earth’s axis; in the altitude of the land; in the
presence of volcanic dust—changes now in cosmic,
now in terrestrial conditions—have been suggested,
combatted, put forward again. None of these hypo-
theses has prevailed in preference to others. No
actual proof of the correctness of this or that theorv
has been brought forward. No general agreement
has been reached. Under these conditions, and in
view of the fact that practical climatology is con-
cerned with climatic changes, not of the geological
362
CLIMATE
past but of the historical present, this portion of our
subject may be dismissed with this brief mention.
Conclusion. There is a widespj-ead popular belief
in permanent, Progressive changes of climate during
a generation or two. This belief is not supported by
the facts of meteorological record. Abundant evi-
dence has been adduced in favour of secular changes
of climate in historical times. Much of this is un-
trustworthy, contradictory, and has been interpreted
without sufficiënt regard to possible Controls other
than climatic change. Without denying the possi-
bility, or even the probability, of the establishment
of the fact of secular changes, there is as yet no suf-
ficiënt warrant for believing in considerable perma-
nent changes over large areas. Dufour, after a
thorough study of all available evidence, has con-
cluded that a change of climate has not been proved.
There are periodic oscillations of slight amount. An
eleven-year period has been made out, with more or
less certainty, for some of the meteorological ele-
ments, but it has been of no practical importance as
yet. A thirty-five-year period is less uncertain, but
is nevertheless of considerable irregularity, and can
not as yet be practically applied in forecasting.
Longer periods are suggested, but not surely estab-
lished. As to causes, variations in solar activity are
naturally receiving attention, and the results thus far
are promising. But climate is a great complex, and
complete and satisfactory explanations of all the facts
will be difficult, perhaps impossible, to reach. At
CHANGES OF CLIMATE
363
present, indeed, the facts which call for explanation
are still in most cases but poorly determined, and the
processes at work are insufficiently understood.
Climate is not absolutely a constant. The pendulum
swings to the right, and to the left. And its swing
is as far to the right as to the left. Each generation
lives through a part of one, or two, or even three,
oscillations. A snap-shot view of these oscillations
makes them seem permanent. As Supan has well
said, it was formerly believed that climate changes
locally, but progressively and permanently. It is
now believed that oscillations of climate are limited
in time, but occur over wide areas. Finally, it is
clear that man, whether by reforestation or deforesta-
tion, by flooding a desert or by draining a swamp,
can produce no important or extended modifications
of natural climate. This is governed by factors be-
yond human control.
-
PART II
CHAPTER 6
THE PRICE OF ACTIVITY
Temperate-zone nations are leaders inworldaffairs.
Their peoples, activated by cool climates, have had the energy
to build great power plants, skyscrapers, dams, bridges, and a
legion of impressive monuments to human initiative. They
visit the tropics mainly for trade and war, and have long benefited
from tropical raw material wealth which the natives were too
sluggish to exploit. But it does not follow that we of the earth’s
favoured regions are less under the control of great outside
forces. While slow-maturing people in hot climates have diffi-
culty losing body heat, our ready ability to get rid of it is a mixed
blessing, since it drives us on to such activity that our bodies
often suffer as a result. A life full of activity and stress is temperate-
zone man’s unconscious response to climatic urging; he himself
has little choice in the matter.
It is this stress which is bringing the most alarming health
menaces to people of the earth’s middle latitudes. The body
seems unable to endure the severe strain thrown upon it by a
constantly increasing pace of activity. Longstanding lack of
proper rest and relaxation tends to leave the system broken and
prematurely old. Even the best of machines must be idle at
times for renovation and repair of worn parts if complete break-
down and early discard are to be avoided. It is in those human
body parts most intimately concerned with supplying the tissue
fires that evidences of breakdown are most frequent.
Oxygen must be carried from lungs to body cells, and it is the
circulatory system (heart and blood vessels) which eventually
suffers most from prolonged forced draft in the human fïrebox.
The red cells of the blood are the real carriers of the oxygen. In
those same regions where heart failure is most common we find
also most frequent exhaustion of the bone marrow which produces
the red cells. This exhaustion is known as pernicious anaemia,
a disease rare in the tropics, but quite severe in middle temperate
regions. Another disease also most prevalent in the stimulating
44
latitudes is diabetes. It represents a breakdown in the body’s
ability to transform the food eaten into the special kind of
sugar which can be burned in the cells.
Proper ease of body heat loss, as made possible by an invigorat-
ing climate, thus works upon man by stimulating his internal
combustion in much the same way a forced-air draught speeds up
the burning of fuel in a steam engine. Stimulated combustion
and a liberal release of energy then drive him into ever-expand-
ing activities, throwing more and more stress on the body parts
which supply oxygen to the tissues. Every good engineer knows
the capacity of his engine, but people seem unable to estimate
properly their own limits. Although they may not be able to
avoid all dangers, a proper appreciation of the value of rest and
relaxation would reduce the risks. Ignorance of these safety
rules results in other forms of breakdown besides pernicious
anaemia and diabetes.
Within the past two years, six of my colleagucs on the Medical
College staff have died of coronary disease and sudden heart
failure—and only one of them was more than fifty-two years
old! Several others have suffered heart attacks, but still survive
with restricted activity. The rest of us up near the half-century
mark are beginning to fear this men ace which is striking down
the most active of our members while still in their prime of
usefulness. Heart failure to-day easily leads among the causes
of death in the northern United States. In 1940, two-thirds of
the deaths among American physicians were recorded as due
to failure in the heart or blood-vessel system! The only near
competitor here in the north is cancer. In the tropics the picture
is quite different, for coronary trouble and heart failure are rare
there except in advanced old age.
Additional emphasis was given to the problem of coronary
disease by an editorial in the April uth (1942) issue of the
Journal of the American Medical Association:
Physicians always advise their patients how to live longer
and better; they themselves often die prematurely of pre-
ventable or at least postponable causes. The prevalcnce of
deaths from heart disease, particularly coronary disease,
among physicians at relatively early ages has in recent years
increased sharply. Coronary disease has come to be known
among physicians as “doctor’s disease.” . . . A new develop-
ment is the Committee of Longevity, Class of 1900, College
of Physicians and Surgeons, New York, which has organized
for the purpose of prolonging the lives and improving the
45
health of one hundred surviving members of the class, which
originally numbered one hundred and seventy-five graduates.
Already the idea has received much pubiicity through editorial
comments in New York papers. Superficially amusing, but
basically significant, is this comment from an editorial in the
New York Sun (July 9, 1941): “Laymen whom middle age
prompts to think of such things are bound to be interested in
the work of the Longevity Gommittee. . . . These doctors
should be able, if anybody can, to propagate the art of col-
lective good health. Laymen will note with an understanding
smile, however,. . . that a good many doctors have this much
in common with a good many laymen: they neglect their
periodic examinations or delay in taking treatment.”
Medical men are much worried about the presence of this
killer among them—a killer which spares the weak and infirm,
but strikes down instead the most energetic and progressive
members of the race. Hardening of the arteries, high blood
pressure, coronary disease, apoplexy—these are the blood-vessel
troubles which incapacitate and kill an astonishing number of
people in the stimulating middle temperate latitudes of America.
Hardening or sclerosis in the vessel walls, often with patchy
roughening of the lining, is the tissue change found at autopsy,
but no one knows yet just what factors of life bring it on. Only
in the last few years have medical scientists been able to repro-
duce and then relieve these conditions in laboratory animals.
Two decades ago the hardening process in the vessels seemed
to take a slower course and resulted more often than to-day in
kidney failure. Rupture of a hardened artery in the brain—
apoplexy or stroke—is about as common as formerly. But the
sclerotic disease now seems to affect the coronary arteries supply-
ing blood to the heart muscle itself much earlier in life and with
much greater frequency than in former decades.
An engineer in his early forties, director of research in a large
Corporation, developed high blood pressure, spent a year and a
half trying to get it back under control, and is to-day assigned
to a minor post of lesser stress—practically finished with life
before he is fifty. A younger human dynamo has just taken his
place in the ceaseless, pushing struggle which cbaracterizes
American business. He too seems destined for the same end.
Keen competition and continuous pressure for results allow him
no rest during the day and keep him keyed up to such a pitch
that he cannot relax properly at night. One of my patients who
will soon migrate to Southern California for sinus trouble is of
46
this same dynamic type. He is already afflicted with hypertension
and coronary trouble before forty-five years of age. One of the
most energetic of my medical colleagues developed a rapidly
Progressive hardening of the arteries and died of heart failure
at fifty. And so it goes, with business executives and professional
men the choice victims of this ruthless enemy.
All this has a very direct and personal interest for me, because
only by careful watch over my winter activities have I succeeded
in keeping sclerosis and high blood pressure at bay. I spent my
childhood and early youth on a farm near Kokomo, Indiana,
where climate acts as a dynamic force on life, and frequent
weather change is a most disturbing influence over the daily
functioning of the body. I had numerous colds and attacks of
sore throat during Indiana winters, and my heart is now quite
sensitive to stress or too much stimulation. No actual rheumatic
heart disease can be found, but the repeated throat infections
probably left some mark on my heart muscle. Palpitation occurs
readily after even moderate smoking or coffee drinking. In
addition, my inner dynamo seems geared for a fast pace of
action. It speeds up through winter cold and slows down in
summer warmth. With the winter acceleration comes a rise in
blood pressure and an inability to relax which several times in
the last twenty years has become really troublesome. Summer
heat brings me a welcome relief from this cold-weather stress,
with the blood pressure settling back to its proper level.
Although I may have particularly good reason to be interested
in weather stresses at present, my study of such matters actually
dates back to my senior year at the University of South Dakota
in 1917. My first bit of research dealt with the effects of high
and low temperatures on the thyroid gland in rabbits. A box
fitted with electric lights served as a hot room, and the outdoor *
Dakota winter supphed ample cold. My wife was pressed into
evening service as anaesthetist while I snipped out small bits of
the rabbit thyroids for microscopie study. We had been married
at the end of our second year in college and were both busy with
regular studies during the day, so these outside experiments
were relegated to evening hours. The next year they were con-
tinued at the University of Kansas, where I went as an instructor
in physiology.
That first piece of work showed the marked stimulating effect
of cold and the quieting influence of warmth upon body functions.
These findings have been expanded and given added emphasis
by later studies. Through the subsequent ten years at the Univer-
sity of Cincinnati, studies on blood clotting and the control of
47
haemorrhage absorbed my energies, and it was not until the
Rockefeller Foundation engaged me at the Peking Union
Medical College in North China that I developed a deep interest
in climate as a major factor in human affairs. I had been bor-
rowed by the foundation from the University of Cincinnati to
work at the college and help introducé Western medical practice
into China. There I encountered my first personal experience
with really debilitating warmth as the Little Heat, Middle
Heat, and Great Heat of Chinese legend piled one on top of
another to make the summer of 1927 a rather terrifying time.
Our younger son was bom during the Great Heat of that
summer. The fight I made to overcome its effects upon him*
helped greatly in opening my eyes to the importance of climate
as a physiological factor in life. For five years it was a nip-and-
tuck battle for his survival, and to-day both he and his mother
bear as “scars” of that experience a troublesome sensitivity to
summer heat. It was during that summer that I began to see
how prolonged heat might cause the body to slow down its
activities and result in a fall in blood pressure, a drop in internal
combustion rate, and a more sluggish pace of living.
My son’s experiences, however, were not all that emphasized
the importance of such problems to me. The significance of
outside forces was brought home by contrast to my own child-
hood. After my farm life near Kokomo I went to South Dakota
with my parents at the age of seventeen to take up residence
under climatic conditions even more invigorating than those
of Indiana.
It was this sort of childhood and youth, brimming over with
energy and activity, which later made a fascinating contrast to
the severe effects of the prolonged heat in Peking. The tropical
lethargy and sluggish life encountered in India, the Malay
States, and South China on the way to Peking impressed me.
It was so ütterly different from the active existence to which I
had been accustomed in temperate-zone coolness. As a child I
always had a particularly strong urge to find out why things
happened as they did. Now I began a really scientific search for
the why of climatic effects.
In China I became my own first guinea-pig, although the
heat affected me less than it did my son. I had spent a most
active winter and spring teaching and doing research after
arriving at Peking late in September of 1926. All was well until
near the end of the next July, when both investigators and
laboratory animals wilted in the severe heat of the Oriental
monsoon season. Tropical lassitude captured me then for the
first time in my life. I neither did nor wanted to do anything
through August and early September, but feit certain that
another good year of work would follow such a complete rest.
October came and went without any urge to work. I took care
of teaching and routine hospital duties, but that top-notch
feeling so necessary for first-rate investigative work was still
absent. Thanksgiving passed and the Christmas holidays came—
still with nothing accomplished. In May families of the foreign
professors were evacuated as the revolutionary forces from
Canton neared Peking, but still I had feit no real urge to work.
Something over which I had no control was slowing down my
accustomed pace of life. Fortunately I had the academie back-
ground to tackle the problem. My first medical faculty post had
been in physiology and I later taught biochemistry and medicine.
# The physiological viewpoint, however, dominated my twenty
years of research. It was particularly applicable to climatic
studies. In Gincinnati I had worked with diabetic patients and
the high blood pressure and heart failure cases which filled the
hospital wards. Consequently, I naturally becarrie interested in
the lack of these diseases among the Chinese people of Peking at
a latitude even slightly farther north than that of Cincinnati.
Why was there less evidence of stress-caused illness among
the Chinese people? The search broadened year by year after
my return to Cincinnati, and before long it began to yield an
insight into the factors at work. A fairly clear picture has finally
been obtained of climatic dominance over man, one which
explains why he is pushed forward impetuously in certain
regions and held back to sluggish pace in others.
It seemed to me that in climate lay one of the basic reasons
why the Chinese people have been so passive in accepting the
domination of more energetic races. The weakening effect of
their severe summer heat is not counterbalanced by vigorous
winter weather such as we have in the northern United States.
Sudden weather changes are much less common than in America
because of a lower level of cyclonic storminess, and autumn
coolness in Peking approaches almost unnoticed. Once the
ground is frozen, it seldom thaws out until spring. People keep
the even tenor of their ways throughout the year, adding more
padded gowns for each few degrees the temperature falls through
autumn and winter, and gradually disrobing again during the
spring rise. The winters are not disturbed by sudden warm spells
or the summers by days of refreshing coolness.
This difference in storminess between Peking and Cincinnati
is perhaps largely responsible for the marked difference in
• # 49
vigour between the people of the two regions. The blood pressure
of Americans usually falls during a few years’ stay in Peking,
and that of Chinese rises when they come to the northern
United States, even without any definite change in dietary or
living habits. Two of my Peking faculty colleagues, both native
Britishers, experienced a 30 per cent. fall in pressure within a
year after returning to China from furloughs spent in England
or the United States. In Peking it was difficult to find enough
cases of hypertension—high blood pressure—for teaching
purposes, while in Cincinnati almost a third of our hospital beds
are occupied by this type of patiënt.
Regions with tropical climates, as well as those with relatively
little storminess, have a relaxing influence on the body and a
Iowering effect on the blood pressure. In 1935 I was sent to the
Philippines by the Leonard Wood Memorial for the Eradication
of Leprosy, now the American Leprosy Foundation, to study
the possible relationship between climatic stimulation and
leprosy. The results of this study will appear in a later chapter;
our immediate'concern is with blood pressure. A blizzard was
raging behind me as the ship left New York in late January, and
I watched my blood pressure drop from 140 systolic and 90
diastolic down to truly subnormal levels in the Philippine heat.
The ship was a 13-knot freighter. As we travelled down
through the soothing Caribbean warmth and up the western
coast of Central America and Mexico, I could feel my inner
machine slow down and the restless urge for action gradually
abate. Soon I was able to sit relaxed for hours on the deck, freed
from the feeling that I should be doing or planning some new
activity. Tropical lethargy is indeed a pleasant state when it has
finally and complctely enveloped one. I can readily see why its
victims would resent being dragged from its dreamy embrace.
By the time I had been in the Philippines a few weeks, my blood
pressure was down to 88 systolic and 60 diastolic (the normal is
120 systolic and 80 diastolic). It rosé slightly after my return to
Cincinnati in May, but not until late the next winter did it
again hit the 130 lcvel.
In Manila I was surprised to find more cases of hypertension
than would be expected in the hospitals of a tropical city, al-
though the number was much less than would occur in an
American city of the same size. The probable reason for this
strange situation seemed again to lie in storm effects, for Manila
lies in the westward path of the Oriental typhoons which sweep
across the Philippines and lash up along the China coast. Al-
though high blood pressure is generally rare in tropical climates,
50
the storminess seems to affect people, to increase the stress of
life and the incidence of the disease. In Manila the net effect of
these two opposing factors resulted in a hypertension rate above
that normaily to be found in tropical centres.
Another sign of a similar interplay of forces was obtained last
year by a young physician in the Canal Zone. Thousands of
labourers are imported from the West Indies for work in the
Zone and thousands of native Panamanians are also used.
All must be carefully examined before being hired. The exam-
inations revealed that hypertension was far more common
among the labourers from the West Indies than among the
natives of Panama. Like the natives of Manila, the West Indians
were much less afflicted than people of the United States, but
they showed more high blood pressure than is common among
tropical races. Again, the only evident difference is that the
West Indies lie in a tropical storm pathway where hurricanes are
frequent, while in Panama cyclonic storms are almost un-
known. The matter needs careful investigation under controlled ,
laboratory conditions and I hope soon to attack it.
-
During the weeks spent in the Philippine heat—in the typhoon-
free season—I developed a real enjoyment of relaxed idleness.
Nothing like this had ever been possible in Cincinnati, even
during summer warmth, for depressing heat here is seldom long
continued without being interrupted by periods of refreshing
coolness. The heat during the summer of 1934 in America was
the most severe and jprolonged of any year within my memory.
That summer I noticed many of us changing to a tropical
metabolic make-up; our tissue fires and blood pressures sub-
sided to tropical levels.
One sixty-year-old patiënt with extremely high blood pressure
and severe distress, whom I had been seeing through 1933 and
the spring of 1934, benefited markedly by the prolonged heat.
His pressure declined and he was quite comfortable, with only
a modest hypertension, when he last visited me four years later.
Every summer brings a moderate fall in the blood pressure of
many people, but it takes a long heat wave to exert any pro-
nounced effect. We have learned, however, that people with
diabetes or limited working capacity of the heart can regularly
allow themselves more freedom in summer warmth without ill
effect.
Few people realize that they expend more energy climbing a
flight of stairs in January than in August, or that the tropical
native can do more work than the energetic northerner on •a
loaf of bread as fuel. He will take a longer time for the job, but
as a working machine he is more efficiënt; he wastes less energy
in maintaining high muscle tone and in useless motions. Not
only are people of middle temperate regions pushed into doing
more because of a rapid tissue combustion, but they are also
more wasteful in the doing of it. These two factors combined are
perhaps largely responsible for the alarming evidences of bodily
and mental breakdown they are now showing.
The rush of city life in itself seems to intensify the stress factors
of life, especially in regions where climatic stimulation is intense.
High blood pressure, hardening of the arteries, heart failure,
diabetes, and all the other evidences of stress are much more
common in the city than in the country. Statistics show that this
applies even to cities of five to ten thousand population, but
probably not to village life. It is important to discover just what
factors of city life are responsible for the appalling evidences of
bodily and mental breakdown which urban populations of
America are undergoing. Your country cousins may appear
unsophisticated, but they live a much saner life and are likely
to remain active long after you have broken under the strain.
Men are far more involved than women in this breakdown,
particularly with the acute types of heart failure—coronary
attacks and angina pee tor is» The worries and effort entailed in
supporting a family are probably responsible for the greater
evidences of stress in men, because breakdown in women is
also accelerating as they too become wage-earners in the com-
merce and industry of cities. Diabetes is now more frequent in
women past forty years of age than it is in men, and hardening
of the arteries is rapidly increasing. Stress in women, however,
shows most frequently in the form of nervous breakdown or
exhaustion. Lack of restful hours in the rush of city life is taking
this toll in the hcalth of both sexes. The effects are less evident
during the early decades of high vitality, but after forty the
human machine begins to show its age. Men in their forties are
usually hardest pushed in their efforts to get ahead, while women
of the same age group or a bit older must face disturbing physical
and mental readjustments incident to the “change of life.”
When knocks and creaks begin to appear in our bodies, it
means that we need longer and more frequent rest periods so
that repair forces can do their work. Proper hours of sleep at
night are essential, but a short afternoon nap is equally im-
portant. Few American men take time out for such relaxation
however much they might benefit by it. Not only do they miss
this rest and reach home thoroughly fatigued by the day’s stress,
but they are then often called upon to go through an evening of
52
social activities with a wife who has been refreshed by her
afternoon nap.
It is probably this lack of rest and relaxation, accumulating
through years of urban existence, which is behind much of the
breakdown taking place in the earth’s most energizing areas.
The northern United States leads the world in this respect, for
nowhere else is the climate quite as driving in its effects or as
upsetting with its frequent storm changes. People of this region
need more rest instead of less, but their energy and restlessness
keep pushing them on at a rapid pace until the collapse comes.
In tropical lands the afternoon siësta is an established custom,
even for most city dwellers. Women migrating from energizing
climates need it, for they are prone to nervous exhaustion if they
try to lead their life of accustomed activity in tropical heat.
One of my medical friends from the Ohio Valley belongs to the
type which succumb in a short time from some form of stress
breakdown if they remain in this stimulating climate. He left
the north early, however, and has spent several active and useful
decades in the tropics. He is now in his sixties, alert and heaithy
—and an afternoon siësta and proper hours of sleep at night are
essential features of his daily routine. Each year he spends a few
months in the northern United States, and his greatest complaint
is the difficulty of obtaining sufficiënt rest.
One of the most refreshing features of a tropical visit for me
is the relaxing afternoon nap, taken in the thoroughly disrobed
tropical fashion. I always come back from a few weeks of such
relaxation well fortified for another year of northern stress.
Summers in Cincinnati are almost as restful, for then I usually
take luncheon at home and sleep for half an hour or so afterwards.
During the winter the stronger urge to be doing something keeps
me on the go from early morning until evening and leaves me
thoroughly exhausted by the end of the day. Temperate-zone
summers should be periods of real biological rest for people who
are hard pushed through the cooler seasons. I myself find'the
winter stress much more trying if I avoid the summer heat by
migrating to cooler regions. A summer spent at Woods Hole
(on Cape Cod) is certainly delightful, but it leaves me less fit
for the next winter’s activities than does a summer spent in
Cincinnati heat.
There are probably few factors which would change the
alarming urban breakdown picture as markedly as the in-
stitution of a regular afternoon siësta and of adequate sleep at
night. The matter is an extremely important one for people
entering middle life, when the body machinery is beginning to
53
show signs of wear from previous decades of activity. Unless
present trends are in some way reversed, civilization in the
earth’s most progressive regions will be truly threatened by this
loss of its most energetic and promising members just as they
reach what should be their most productive period. A man at
fifty has gained valuable experiences which increase his value to
society from then on to old age. It is more important that his
life be spared for another decade or two than that a few more
babies be saved from the hazards of infancy and early childhood.
Medical science is faced with a serious need for better methods
of handling the health problems of middle and more advanced
ages.
The basic need is that men learn the art of living a hygienic
life. Once disease actually appears, particularly that of the
breakdown type, it is often too late to repair the damage. This
is almost as true of nervous breakdown as it is of heart failure,
for in either case the stricken individual remains crippled for
life. It is difficult to get people to see this, however, until they
themselves have suffered—and then the time for healing has
passed.
> Americans in the prime of life often say they prefer a fast pace
and a merry one, come what may at a later age. But life assumes
an entirely different aspect once the break has come and they
are faced with the necessity of living on under sharply restricted
conditions. As a result, they advise the younger generation to
take life lcss strenuously, but young folks pay little attention.
Their exuberant energy pushes them-on in the never ending
rush and hurry, and the destructive round of work, unalleviated
by true relaxation, continues. We are becoming all too famiiiar
with the results.
chapter 7
DRUGS AND STIMULANTS
Eating and drinking habitsoftengreatlyaccentuatethe
effects of climatic environment. In the tropics people need extra
supplies of the B vitamins, yet they eat meats low in these
dietary factors and cook them so long that even the reduced
content of valuable ingredients is destroyed. The net effect is to
further emphasize the lethargie pace characteristic of hot
54
climates. An opposite but equally unfortunate set of circum-
stances exists in energizing temperate-zone climates, where men
are driven to restless activity in their daily lives, yet turn too
frequently to drugs and stimulants which place a further burden
on their straining bodies.
Caffeine—the stimulating factor in coffee, tea, and cola
products—provides an excellent example of this sort of habit,
It is the ideal stimulant for the body tissues when properly used
but its abuse probably constitutes the most widespread drug
addiction among mankind to-day. Any regular devotee who
develops a headache when the drug is omitted for one day
should consider himself in that class—a private in one of the
largest armies on earth.
Caffeine speeds up the burning of food in the tissues and
increases their functional activities. Mental processes become
keener, the heart works harder, reflexes are quickened, special
senses become more acute, and in every way the body becomes
more highly alive and vital. All this happens, however, only if
the tissue response has not been dulled by habitual and often-
repeated use of the drug. Being such an active stimulant, its
continued use tends to bring on an exhaustion calling for ever
increasing dosage.
Although originated and produced in tropical lands, coffee
is consumed principally by people of the temperate zones.
Well over half the entire world output is used in the United
States—more than 2,000,000,000 pounds a ycar or probably an
average of almost a pound each week for those who use it.
Heaviest consumption is in the northern States.
Most users freely admit that they drink coffee for the pick-up
and feeling of increased strength it gives. They like its help in
carrying them through the day’s stress, and probably for this
reason it is used most heavily by people of the stimulating
climates. For persons already subjected to the strain of a too
rapid pace of life it does provide a transitory sense of fitness and
efficiency. But its habitual use only intensifies the underlying
exhaustion of body tissues which is to-day leading people of the
invigorating regions into a most alarming breakdown.
Among ship’s captains coffee is almost an occupational
necessity. While en route to the Philippines in 1935 as the only
passenger on a cargo ship, I was urged by the captain to try a
sample cup of special coffee they had just taken on at Honolulu.
He praised it highly as being able to keep him awake when no
ordinary coffee would and used it for periods of protracted stress
at sea when he had to remain on the bridge without sleep for
55
days at a time. I am not a regular user of caffeine and am quite
sensitive to its stimulating eifects. So I managed to resist his
urgings for 4 few days. But he finally sent the steward with a cup,
catching me while I was playing chess with the chief engineer.
As the captain said, it was really delicious coffee, and enabled
me to go ahead and win three straight games. I had not the
slightest urge to retire that night, however, even though I had
nothing else to do except read the rather limited material at
hand. The second night I went to bed, but was unable to sleep.
The third I dozed off for a couple of hours, but it was not until
the fifth night that I managed to get as much as six hóurs of
sleep! After that experience I could appreciate why the ship’s
officers preferred to have this brand of coffee available in times
of emergency when they had to keep awake. It naturally affected
them less than it did me because they were all regular users
of caffeine, but even so they used this brand only on special
occasions.
The captain himself regularly drank about twenty cups of
coffee daily, as nearly as I could estimate. Since such heavy
coffee use is customary with those responsible for a ship’s safety
at sea, I can readily see why they so often come to an early end
by sudden heart failure or apoplexy. Since then I have found
much heavier users of coffee, and among people without such
responsibility or special need for wakefulness to justify their
over-indulgence. One extremely nervous woman claimed that
she was drinking about 60 cups daily, her son about 30, and a
grandson 15, the three of them using over a pound of coffee each
day. Another woman, complaining of great nervousness, sleep-
lessness, headache, palpitation, and weakness, was herself
using 3 pounds a week!
Such extremes, of course, are a form of slow if not very subüe
suicide, especially in northern climates. But tropical natives may
use caffeine with little danger of ill effects since their capacity
for response to its stimulating action is low. Even I can use it
almost regularly after being calmed down by a month of tropical
heat. With the higher combustion rate of northern winters,
however, I find it entirely too dynamic for continued use. These
pages are being written under caffeine influence, for it does induce
a ciarity of thought seldom achieved otherwise. But even my
single early morning cup must be discontinued after a week or
so if troublesome nervous tension is to be avoided.
Coffee and caffeine are being used interchangeably because
coffee provides by far the major part of man’s supply of this drug.
About four times more coffee than tea is used throughout the
56
world, but in America the ratio is more like twenty to one.
Orientals—particularly Chinese and Japanese—are heavy tea
users, while in Europe the two are more evenly balanced. Tea
leaves contain roughly twice as much caffeine (or simliarly
acting substances) as does coffee, but methods of brewing the
two beverages are so varied that either may contain more
stimulant per cup as consumed. Americans are noted for brewing
coffee of pleasant taste and powerful stimulating effect. Curiously
enough, it is in the invigorating climate of the northern States
that this art of brewing has been most highly developed.
Cola nuts form an important caffeine source for tropical
natives, and their extracts are used in many popular cold drinks.
Hundreds of thousands of Americans obtain considerable caffeine
in consuming enormous quantities of these beverages. The
demand is particularly strong among children and young folks
who use little tea or coffee. It has been said that 5,000,000 pounds
of pure caffeine go into the cold drinks manufactured each year,
making some of them almost as potent stimulants as coffee. It
is heartening, however, to learn that the manufacturers of one
of the leading American bottled beverages have progressively
reduced the caffeine content until now it is only a half-grain per
bottle—as compared to the three grains or so in a cup of coffee.
Caffeine merits detailed attention because it is intimately
related to climatic drive all over the earth and to the human
stress which is becoming so devastating in regions where this
stimulation is most intense. Although caffeine is valuable for'
brief periods of need, its over-use to whip up the flagging spirits
of people already jaded by over-intense stimulation is a most
irrational procedure. Not only does the drug—by masking
underlying fatigue—permit people to perform more daily work
than their systems can stand, but it often cuts down one’s valu-
able sleeping hours. Contrary to common belief, the effect does
not wear off entirely within two or three hours. The nervous
system remains over-excitable for many hours, upsetting the
relaxation necessary for a good night’s sleep. This deadly com-
bination of overwork and lack of rest gradually leads to physical
or mental breakdown.
Although most physicians themselves like their cup of coffee,
more and more of them are coming to see it as one important
factor responsible for the increasing frequency with which heart
failure is striking down members of their profession. Thoughtful
medical men now recognize that caffeine throws added work
upon the heart to support the greater bodily activity which it
makes possible, and that use of the drug should be prohibited
57
when the heart’s working capacity is in any way impaired.
There is also some evidence that it causes contraction of the
vessels and a rise in blood pressure. In many cases of hyper-
tension elimination of caffeine from the diet results in a consider-
able fall in blood pressure—unless advanced hardening of the
vessels has already taken place. At the first hint of coronary
trouble the wise physician now prohibits the use of all caffeine-
containing beverages.
Some weeks ago a woman neighbour complained of being
easily fatigued. She had pain in her shoulders and was nervous
and weak. A local physician merely diagnosed her condition
as high blood pressure and advised the woman to have all her
teeth pulled. The price he quoted for the extractions and the
fact that all his patients had been discussing such loss of teeth
aroused her suspicions. Thinking that he might be one of those
who profit by this overworked tooth-pulling idea, she asked my
advice. I suggested Consulting at least one other reputable
physician or dentist before giving up all her teeth, adding that
meanwhile she should give up coffee and see if that would not
relieve the high blood pressure and most of her symptoms.
This suggestion took her quite by surprise, since the first physician
had not brought up the subject. She and her husband were
rather heavy coffee-drinkers, and their children often drank
cola beverages. After a few weeks, however, she reported her
condition much improved.
-
.
* Two other women about forty years of age also came to me
with similar complaints a year ago; both obtained complete
relief from their high blood pressure and the resulting symptoms
by cutting out caffeine ‘ entirely. Another woman of the neigh-
bourhood ploughed her way straight to a severe nervous break-
down with a coffee cup in one hand and an aspirin bottle in the
other—but her physician never suggested that she avoid caffeine.
A cautious hint finally caused her to try caffeine-free coffee, but
the damage to her nervous system can never be completely
repaired. It is an old and often heartbreaking story to see the
devastation wrought by this delightful beverage among energetic
northerners and the frequency with which doctors overlook this
factor.
Just recently a mother brought her fourteen-year-old son for
examination and asked me to find the reason for his retarded
development and poor school record. He was a very nervous
boy, undersized and malnourished, but without symptoms of
any disease to account for his condition. His heart action was
rapid and extremely forceful, however, and upon inquiry I
58
found he regularly drank cofTee for breakfast and usually had
caffeine in some form at least twice a day. He was of German
stock and had been started on the drug as a baby, actually being
given a mixture of half cofTee and half milk in his bottle. This
seems to be rather a common practice among many Gincinnati
people.
Several times in Boy Scout work I have listened to a number
of hearts in sucession and been able to piek out the boys who
were under the influence of caffeine at the time of examination.
Ghildren are particularly susceptible to its effects. A careful
survey of several hundred school children a few years ago re-
vealed that those who used caffeine regularly in any form were
considerably retarded in development as compared with other
children of similar economie level. I explained all this to the
mother of my fourteen-year-old patiënt and finally obtained her
somewhat reluctant co-operation in getting the boy to abstain
from all caffeine-containing beverages. Two months later she
reported that he was sleeping more soundly, progressing well in
his studies, and was much more manageable at home.
Such experiences with the effects of caffeine on children have
been repeated many times each year. They have finally led me
to condemn most emphatically its use in childhood or early
youth. Even during college years, when thq days are too short
for crowding activities, caffeine usage is very likely to be over-
done. It adds temporary sparkle and vivacity to the individual,
but is likely to reduce efficiency in the long run. The practice of
taking cofTee to study late the night before examinations is
particularly bad. A much wiser procedure is to get plonty of
sleep beforehand and then take stimulating caffeine about an
hour before examination time.
It is encouraging to note the increasing use of caffeine-free
cofTee. Many thoughtful hostesses keep it on hand and inquire
regarding the guests’ preference. Some serve it instead of regular
cofTee without comment, but this shows little consideration for
certain people, who will most certainly develop a headache
without their regular caffeine. Particularly heartening also is
the fact that most college students drink milk in their cafeterias
and dining halls, although tea and cofTee are available.
From the climatic standpoint, over-use of caffeine is a most
dangerous and pernicious habit, since it usually developes in
those very regions where people are aiready driven at too fast a
pace by the urgings of climate itself. Wide individual variations
exist in people’s response to the drug, so that no one should
consider three cups of cofTee safe simply because he knows others
59
who drink that much with ^pparent impunity. People of the
northern United States should develop far greater moderation
in caffcine usage and realize its close relation to the other stress
factors which are bringing so many to a premature end.
To introducé the discussion of another popular drug, nicotine,
I can think of no better anecdote than the following from the
Progressive Farmer: Aunt Becky was punctuating the Negro
preacher’s sermon with “Amen! Amen! . . . Praise de Lawd!
..as he lit into every sort of sin from murder to shooting craps.
Then the parson moved on against snuff-dipping, and Aunt
Becky exclaimed to her neighbour indignantly, “Dar now!
He’s done stopped preachin’ and gone to meddlin’!”
Many patients assume a similar attitude when their family
physician gently suggests that they stop smoking, but the advice '
is usually sound. Though evidence is still far from satisfactory
or complete, indications are that in many people smoking induces
a blood vessel spasm or contraction which interferes with proper
functioning of* the vascular system. Such a spasm has been shown
quite clearly for at least certain parts of the system. And thus,
though physicians in general are heavy smokers, they have
become somewhat more wary in the last few years. The astound-
ing increase in coronary heart trouble is making them more
suspicious of any factor which may accentuate vascular troubles.
The use of tobacco—as well as caffeine —is now strictly pro-
hibited at the first sign of serious coronary trouble.
The way several heavy smokers among my associates suddenly
became total abstainers in recent months would have been
amusing if it had not been so closely associated with the tragic
faculty deaths. The most confirmed smokers, who previously
refused to believe that tobacco was in any way harmful, now
stopped smoking entirely.
One of my colleagues who died two years ago of coronary
heart trouble had been a confirmed “chain” smoker for many
years, lighting onc cigarette from the burning stub of the pre-
ceding one. After his first coronary attack he quit both coffee and
tobacco for almost two years. Habit finally reasserted itself,
however, and shortly before his second and fatal attack he was
smoking as hard as ever. Most victims of these attacks are heavy
smokers, usually men. In recent decades, however, women of
the younger generation have been smoking almost as much
as men, so it will be interesting to see whether they also
become more susceptible to this disease through the coming
years.
I myself have never smoked much, but even four or five
60
cigarettes a day tend to make my heart beat irregularly and blur
my intellect. Many smokers use two or three packs a day without
direct evidence of harm, and yet there is a growing feeling that
such immoderate use of tobacco may eventually be harmful.
Cigars are worse than cigarettes, particularly if they are smoked
down close to the butt. The harmful ingredients of tobacco
smoke may be largely removed by absorbant filters, but these
must be changed frequently to be effective.
It is indeed urifortunate that no clear case yet exists either for
or against the use of tobacco. Within moderate limits it may be
quite harmless for most people living in regions where stress on
the vascular system is not severe; but in the earth’s stimulating
areas much greater caution should be exercised. Just as with
caffeine, it is the restlessness and tension of life in the stimulating
climates which lead people into excessive smoking. The act
itself is usually an expression of this restlessness and lack of rcpose,
especially cigarette smoking. Hence we see the most excessive
and harmful overuse of tobacco among the very people who
should be most on guard against its effects.
Caffeine and nicotine are not the only commonly uscd drugs
which have a direct bearing upon man’s reaction to climate.
Coffee and tea became popular in Europe only in the sixteenth
century, about the same time tobacco was introduced from the
New World. But alcohol has always been with us and had its
large army of devotees back into the most remote recesses of
antiquity. Highballs, wines, beers, and the numerous other
drinks in such demand to-day have had their counterparts all
through human history. Probably the first recordcd use of an
alcoholic beverage was by Noah as describcd in Gen. ix. 21, only
nine generations after Adam. For revelry and a free flow of
emotions alcohol has always been in demand.
Delirium tremens patients who enter our hospitals as complete
nervous wrecks, however, represent a type of case seldom seen
elsewhere than in the temperate zones. It was perhaps not
chance alone that the first temperance crusade took place in the
invigorating, stormy climate of the western plains when Carrie
Nation, with her axe, led a revolt against the most vicious and
destructive effects of alcohol. In warmer regions where human
energy is low alcohol produces only a mild excitement phase
which quickly passes into drowsiness or lethargy. With energetic
people of cooler lands, however, the early excitement phase is
more marked and often leads to extremes of ill-considered vio-
lence. Alcoholism has a curiously strong tendency to produce
troublesome social problems in these regions. Only among
61
energetic people of cool climates is the old Indian term “fire-
water” particularly appropriate.
The reason for this climate difference in response is found in
the effects of alcohol upon the brain cells. It is not a stimulant
in any real sense. It does not increase cellular combustion or
tissue activity in the way caffeine does. Being a near Chemical
relative of the simple sugars, alcohol is burned as a food in the
cells. lts chief physiological action is upon the central nervous
system, particularly the brain. Here it acts as a narcotic with a
deadening effect upon the brain cells. The cells of the highest
centres in the cerebrum are most susceptible to its action—they
are the centres having to do with judgment, moral sense, in-
hibitions, and with the other high psychic phases of existence.
As the cells of these higher centres become deadened by the first
effects of alcohol, the centres of lower order are allowed freer
play in determining actions and conduct. Basic emotions—those
of sex, anger, affection, and the like—thus escape from the
inhibiting influences of the higher centres, and existence drops
closer to the animal level of direct response to every impulse.
Among tropical people of low energy this release from higher
inhibitions means little. Fewer inhibitions ai;e needed or are
present where the urge to action is low. The tropical native acts
almost as freely when sober as when under this releasing effect
of alcohol. He seldom has an excess of energy which requires
curbing or which gets him into trouble when his higher inhibi-
tions are dulled by alcohol. But inhibitions are socially necessary
among the dynamic residents of cooler climates where tissue fires
bum faster. As alcohol dulls the inhibitions, chaotic situations
may arise only too readily and lead to disaster.
A man in his early forties came to me recently for advice
regarding his drinking habits. He had been happily married for
eleven years and had three fine children. The home life of the
family had been pleasant in all respects except that a sharp
limitation of income had made them live a most economical
life. Income had not increased as the family grew in size—it had
in fact shrunk during the depression years—and the financial
oudook had become more and more hopeless as debts began to
accumulate. About a year ago the wife told me her husband was
drinking considerable quantities of wine in the evenings after
coming home from work. This interfered with his tasks next day
and further intensified the family’s economie problem.
The man seemed beaten by his long years of worry and lack
of financial progress. He had no force left to fight the hold alcohol
was taking on him. Only through its deadening influence could
62
he forget his feeling of frustration and despair. He seemed
earnesüy to desire help, so I sent him to a good psychiatrist—
but to no avail. The spirit was willing but the body weak. At
present he is'attending nignt school, training himself for a better-
paid type of work in one of the key defence industries, and seems
to have taken on a new hope at this prospect of a solution to
his financial problems. But he is still drinking and will need
something more powerful than mere hope to bolster his ego.
Only real success can now fortify him against the desire for the
deadening effects of alcohol.
Here is a man worn down and almost defeated in the keen
economie fight to support his family adequately. Alcohol affords
him temporary escape from the hard realities of his problem,
but its use only makes the situation more precarious. This
experience has been repeated in millions of families of every
generation back through the centuries and has been one of the
chief factors behind the development of the temperance move-
ment in Europe and America. Such people really need sympathy
and help, for theirs is an economie failure and alcohol soon robs
them of even their small earning capacity. Their problem is most
acute in regions where life follows a rapid course and the scale
of living is high, for failure shows up most sharply there. Few
bother about such matters where tropical complacency prevails.
A fellow investigator at Cincinnati showed that one of the
chief damaging effects of alcohol is due to the fact that it lacks
the B vitamins. These are just as necessary to facilitate the
burning of alcohol in the body tissues as they are for the burning
of the chemically related sugars. Normally the foods which
supply our tissues with sugar contain these important vitamins,
but alcoholic beverages contain practically no vitamins of any
sort. In addition, people heavily addicted to alcohol often have
little appetite for regular foods because the burning of alcohol
has replaced that of sugar. Thus they readily develop vitamin
deficiencies, particularly pellagra from lack of proper nicotinic
acid and nervous or neuritic symptoms from lack of Bi or
thiamin.
Drinking affects the brain cells immediately because they
contain a higher proportion of special alcohol-absorbing fats
than most of the body’s other tissues. But later brain effects from
prolonged addiction seem to be due mosdy to B vitamin de-
ficiency. The brain has the highest combustion rate of all body
tissues and hence requires the greatest supply of these vitamins
catalysts. Jittery, highly irritable alcoholics who are nearing
the convulsive stage of delirium tremens now promptly receive
63
large amounts of the vitamins and plenty of nutritious food when
they come for treatment.
The drinker who becomes quarrelsonle, unruly, and violent
under the influence of alcohol has provided society with the most
acute phase of the liquor problem. As we have emphasized, he
is predominantly a product of the earth’s most stimulating
climate. His abundance of energy runs riot as alcohol dulls the
inhibitions which normally keep antisocial impulses under
control. His excesses may take almost any form, but they usually
involve the very fields of morality most closely guarded by
inhibitions during normal life. Sexual excesses, assaults upon the
person and property of others—these are the lines most often
followed by his unbridled energy.
In those regions where life is most strenuous, perhaps the most
justifiable use of alcohol—outside of its applications in medicine
—is the late afternoon or evening cocktail or highball to relieve
the brain from the day’s stresses and worries. This may be
relatively safe for strong and successful persons, but uncontrolled
addiction is likely to result among those who find life’s battles
too severe. Many women of American cities who flounder in
aimless idleness are among to-day’s heavy users of alcohol.
The very futility of their existence inclines them to alcohol and
other narcotics which dull their appreciation of life’s unsatis-
factory aspects. People really do “drown their sorrows and
disappointments in drink,” but at the same time they frequently
drown themselves in permanent alcoholism.
The threat of drinking is especially great among those who
migrate from energizing climates into tropical heat. Many of
these persons, especially the women, develop a feeling of frustra-
tion because of life’s slow pace and prevailing physical inactivity.
Extremely sad cases of chronic alcoholism have developed among
the wives of prominent men who have had to Jive their lives in
the stagnation of tropical service. Heat subdues the tissue fires
and leads to less rapid burning of the alcohol absorbed into the
blood, thus making such people more susceptible to its narcotic
effects.
This is perhaps the first time the alcohol problem has been
considered from a climatic point of view, but such an approach
is extremely appropriate. It makes quite evident the reasons why
the temperance movement is largely restricted to the most
energizing regions of the earth. The hard-driven people of cooler
lands are most addicted to overuse not only of alcohol but of
caffeine-containing beverages, tobacco, and narcotic drugs
such as morphine, cocaine, and heroin.
64
One of the great unsolved problems of life in energizing
climates is how to avoid the dangers of bodily and mental stress
described in this and the preceding chapter. Scientists and the
medical profession are finally awakening to the serious hazards
which such strain is bringing to man in regions where his past
progress has been most astonishing.
chapter 8
STORMY WEATHER AND RESPIRATORY
INFECTIONS
Last winter a worried man of middle age came to my
office. In approved medical style, we shall keep him nameless and
refer to him only as Mr. X. This patiënt wanted me to help him
solve the problem of chronic sinusitis which was making life
miserable for himself and his family. As far as physical symptoms
went, Mr. X was a typical sinus sufferer, so his case shall be a
guiding example throughout this chapter to illustrate the
climatic do’s and don’t’s of this most annoying affliction. He
differed from most victims of the disease in' that he had an
intelligent and realistic viewpoint, considering good health
more important than money-making. Although a successful
Cincinnati manufacturer, he was willing to move permanently
to any region where he would have a definite chance to enjoy
life more fully. Because of his sane attitude, it was a real pleasure
to discuss with him the climatic and weather factors influencing
respiratory infections in different parts of the country.
Throughout his life Mr. X had suffered from nasal catarrh—
chronic sinus trouble—having lived in the changeable weather
of Cincinnati, where the atmosphere is highly polluted with the
irritating products of soft-coal fires (soot, silicate ash, and
sulphur gases). For generations nasal catarrh had been the
curse of his family, just as it is in countless other familues living
in stormy regions of the earth.
-
Both his father and his grandfather had been similarly afflicted.
His only child was already developing chronic bronchitis. All
members of the family suffered with frequent colds. The entire
case history was characteristic of the disease, which runs in
families for two main reasons. It often begins because a highly
CCMM 65
arched palate in the mouth has pushed the central partition of
the nose to one side and obstructed the opening to one of the
secondary cavities. This was the case with Mr. X. As long as
these cavities or sinuses remain open and well drained they
cause little trouble. But when the opening is obstructed, every
acute nasal infection which comes along settles there for a
prolonged stay, and soon a chronic sinus condition develops.
Since shape of the face and likelihood of a highly arched palate
are strongly hereditary (as our patiënt learned to his regret),
so also is the tendency to chronic sinus trouble. But other causes.
such as childhood adenoids and mouth breathing, can lead to
the samc arching of the palate.
Although Mr. X inherited an arched palate and this is suffi-
ciënt to explain his case, the second reason why sinusitis may be
a family curse is also of interest. One affiicted member of the
family is likcly to spread the disease into the sinuses of others in
the household. Every “cold” organism brought home from
outside by the children lodges in that good growing spot, grows
merrily in the poorly aired cavity, and becomes more virulent.
Later it finds its way into the sinuses of others in the family.
Thus one chronic case in a household usually means frequent
colds for all and an excellent chance for sinusitis among those
persons who, because of hereditary or acquired predispositions,
happen to offer fertile fields for infection. Persistent bronchitis
and the tendency to frequent colds can often be traced to the
presence in the household of a person with chronic sinus in-
flammations. In one Cincinnati family a change of maids finally
clcared up the respiratory troubles. But if the sufferer happens
to be a paren t, the remedy is not so simple and a change of
location might well be considered.
A previously broken nose may also start a long line of sinusitis
sufferers. The break usually pushes inward on the nasal partition,
bending it and obstructing a sinus opening off to the side. My
wife suffered such an injury during a high-school basketball
game, but scarcely noticed it until she was swimming two years
ago and broke her nose again. Typical nasal catarrh then set in
and I sent her to a surgeon for a so-called “sub-mucous resection”
or cutting out of the cartilage in the dividing partition. This
operation, followed by a mid-winter trip to the steady warmth
of Panama, effected a complete cure and probably saved our
family much trouble. An interesting feature of the hospital stay
was her loss of smell while her nose was packed with gauze
following the operation. At the very time when a patiënt needed
to be coaxed by attractive delicacies, she complained bitterly
66
of the poor, tasteless food served. It was not an amusing matter
to her, considering the daily rates charged by the hospital. To
this day she will not believe that everything seemed tasteless to
her simply because she couldn’t smell the food odours and that
by far the greater part of food tastiness depends on a keen
smelling apparatus.
Fortunately, sinusitis is not a fixture in our family a5 it was in
Mr. X’s. As it happened, he was not content to sit back and
continue under the same conditions which had resulted in
generations of ill health. The only thing for him to do was to
migrate to a more favourable climate—and that involves the
fascinating geography of sinusitis. One thing was certain: Mr. X
could not remain in Cincinnati, for this city is extremely stormy,
and sinusitis, like high blood pressure, is most prevalent in the
world’s stormiest regions. As yet no onc knows exactly what
storm changes in the atmosphere do to our bodies, but thcy
seem linked in some fashion to the initiation «of sinusitis and
acute respiratory and rheumatic attacks. There is some cvidence*
that our tissues take up more water and swell as the outside
barometric pressure falls and then give the water off through
the kidneys after the storm centre has passed on. We appear to
be somewhat spongelike in this regard, and the change in tissue
water content may well interfere with our resistancc to inlection.
Whatevcr the mechanism of this storm effect, it is true that
acute respiratory and rheumatic attacks are most frequent in
stormy regions and during the most stormy scasons of the ycar.
Colds and other respiratory infections are less troublesome
during the summer, not because of a greater vitality from the
more intense sunshine, but rather because of the reduced summer
storminess. Actually, the body’s ability to fight infcction falls
during periods of prolonged warmth and is highest when body
heat can be rcadily lost. Therein lies an extremely important
point in connection with any considered change of residcncc for
climatic benefit.
I had to consider these and other factors before telling
Mr. X where to move for a happy life. Although Cincinnati is
not the worst place on earth for storminess and sinusitis, it
certainly ranks high and was no spot for my patiënt. Similar
conditions prevail throughout the upper half of the Mississippi
Basin from the Rocky Mountains to the Appalarhians, where all
respiratory troubles are common. The low'er half of the Ohio
Valley lies under an even blacker curse. This is probably the
chief sinusitis zone in the United States. It also has the nation’s
highest tuberculosis rate. Cities in the Ohio Valley are near
67
producing fields for the poorer grades of soft coal, and their
atmospheric pollution probably intensifies the respiratory
disease hazard (this possibility calls for immediate and thorough
investigation).
Obviously, neither the Ohio Valley nor Cincinnati would do
for Mr. X, and from past experiences I also eliminated many
other regibns. For example, when I was in Manila a few years
ago, I was asked to see another person from Cincinnati who had
taken his Ohio Valley chronic sinusitis to the Philippines, but
without any relief. We should expect this from the last chapter,
which emphasized the storminess there. The northern half of the
Philippines lies in the Orient’s major typhoon pathway, and these
low-pressure storm centres often play havoc in Manila itself.
Whether as a result of these circumstances or not, it is a fact that
sinusitis, tuberculosis, and the other more chronic respiratory
complaints are almost as common there as in the upper Missis-
sippi Valley. On the other hand, the depressive moist heat
prevailing in Manila sharply reduces the ability to fight these
infections. Tuberculosis runs a rapidly fatal course and sinus
troubles go unchecked. Mecjical friends from Puerto Rico inform
me that a similar situation also exists in the West Indies hurricane
belt. It is a curious fact that only in these two tropical storm areas
are acute appendicitis attacks as frequent and severe as in the
Mississippi Valley. For some unknown reason appendicitis
attacks also are prone to come on days of falling barometric
pressure as a storm centre is approaching or passing.
I explained all this to the Cincinnatian in Manila, but his
business and family ties seemed to bind him to a choice of
Manila, Cincinnati, or New York City as a place of residence.
Of these three locations New York would perhaps offer a slightly
less severe respiratory handicap, but none of them offers much
hope for relief from chronic sinus trouble. I have not seen this
man for several years, but my guess would be that he still has
his chronic sinusitis, with perhaps a chronic bronchitis now
added to his troubles during the winter months.
Although Mr. X had lifelong business ties in Cincinnati, he
was willing to break all connections to get rid of his condition.
Parts of Colorado or Southern Florida have most excellent
climates, but, as far as this patiënt was concerned, the one is
too close to winter storm pathways coming down from the north-
west and the other is afflicted by hurricane-type storms which
sweep in across the West Indies and northward up the Adantic
coast. When I had told him about this relationship between
storminess and sinusitis, I also dismissed certain seemingly
68
possible regions as out of the question. He could have escaped
all storm effects by migrating to Panama, Hawaii, or any
number of calm tropical areas. Broad reaches of the tropics are
free from both the cyclonic storminess of the temperate zones
and the typhoon or hurricane types which afflict limited other
parts of the tropics. But if he migrated into tropical warmth,
the ability of his tissues to fight his sinus infection would be
reduced and his troubles would persist. What he needed was
freedom from storms without the depressing moist heat of the
tropics. Even along the Gulf coast of our Southern States the
prolonged moist summer heat has this depressive effect.
But there happens to be one important section of the United
States where respiratory troubles in general are at a minimum
and where chronic sinusitis in particular has an excellent chance
of lapsing into almost complete inactivity. Sudden storm changes
seldom occur in the South-west, a large and favoured region
including New Mexico, Arizona, and Southern California. As I
pointed out earlier in this chapter, Mr. X was intelligent and
anxious to obtain every possible advantage from his change of
location. I told him that the climate of Southern Arizona or
New Mexico would be best for his catarrh, but he was a clothing
manufacturer and needed contact with a large urban centre
for business reasons. This narrowed the choice quite drastically,
leaving only the Los Angeles metropolitan area.
It was somewhat against my better judgment that I finally
recommended this area as a future home for this family. Mr. X
happens to be afflicted with moderately high blood pressure and
some anginal pain over his heart. The dry, non-stormy climate
of Southern California will unquestionably lessen the family’s
respiratory troubles, but there is a restlessness and artificiality
among the people which will not help this man’s coronary
trouble. Although the climate of Los Angeles is certainly not
stimulating, one is aware of a rush and urgency seldom en-
countered except in the most invigorating climates. Driving
speeds on the main thoroughfares seem faster than in any other
metropolitan area. Much of the rush might be explained by
migration there of restless people from all over America, many
of them seeking quick fame and others diversion from previous
dullness elsewhere. Generally life follows a more sedate course
in less stimulating climates.
My patiënt was warned about the disturbing influences around
Los Angeles and was advised to establish his home in the out-
skirts of the city well away from all the hustle and bustle. San
Diego would have been an even better place for him to live, but
69
the greater isolation from his business world would have been
an added economie handicap offsetting the slightly greater
heaith benefits. Having located Mr. X’s fiiture home in Los
Angeles and, more specifically, in one of that city’s quieter
suburbs, ‘I also gave him several important additional hints.
For example, I told him to select a home site at as high an
altitude as possible within commuting distance pf his future
place of business. Although daytime heat is dry in the
South-west, the temperature is sometimes enervating and
even the midday heat is less severe at moderate elevations above
sea-level.
Another suggestion was that he live back as far as possible
from the coast. You may wonder why I told this patiënt to stay
some distance away from the ocean and its delightfully cooling
breczes—but there is a good reason. Air movement there along
the coast is always inland, carrying salt spray and mists, so that
the climate of the Coastal fringe is very different from that of the
desert regions some miles farther inland. Nothing seems to
benefit sinus infiammation so much as the non-stormy dryness
of desert climates.
A few summers ago my family spent the month of August in
a cottage directly overlooking the ocean south of Santa Monica
and lound the cool ocean breezes a most welcome relief from
Midwcst heat. Ho wever, the winds off the ocean were quite
moist through the night and most of the forenoon hours. Before
the month had passed two of us had dcveloped definite sinus
trouble which persisted until we started inland across the deserts
on our return trip. Daily bathing in the surf among the massive
breakers and churning sand probably did much to keep our
sinus infiammation going. It is unwise for a person with sinus
trouble to bathe in salt water or strongly chlorinated pools
unless he avoids getting water into his nose, because water in
the sinus cavities irritates delicate lining tissues. After that
experienced with moist California Coastal breezes, I could easily
see why people with sinusitis or nasal catarrh should locate
faither inland.
Mr. X wanted to obtain every possible advantage from his
change of location. It takes courage for a man to break off all
his lifelong relationships and give up a successful business just to
seek a more healthful location, but he had seen enough of the
continual misery brought by sinusitis in the Midwest to be
wïlling to face the economie risks of such a move. In my opinion
he exhibited a realistic wisdom which a great many other
northerners could well imitate. Good heaith is worth more, even
70
at a lower economie level, than is a life of wealth always over-
shadowed by physical discomfort and chronic ill health. He
intends to move to Los Angeles soon, and I am certain that he
will suffer far less because of his decision.
He is probably avoiding a great deal more than sinus trouble
alone, for in stormy climates this malady is only the beginning
of ill-health. Germ-laden secretions and pus from the involved
sinuses drop down into the air passages and lungs during sleep
and soon set up chronic bronchitis. This goes on year aftcr year,
slowly growing worse with each winter and moderating some-
what with the calm warmth of summer. Eventually the smaller
air passages develop dilated portions filled with pus and then
the person has bronchiectasis. His cough is then practically
continuous throughout the year, with largc amounts of foul
sputum being expectorated at all times. Every acute respiratory
infection acts almost like an attack of pneumonia in setting up
severe inflammation throughout the diseased air passages and
subsiding at an irritatingly slow rate. For such people life is a
dreary round of coughing and expectorating, with one actitc
flare-up following another through the stormy seasons.
It is this slow spreading of trouble from chronic sinus infections
which makes the matter so important for futurc health. Usually
only one sinus cavity is involved at first. The trouble tends to
spread to other sinuses, however, then down the air passages into
the lungs. Nose and throat spccialists can often help clear up a
sinus infection while it is still in its early stages, bul they usually
have little success when it has become chronic. Chronic sinus
patients provide lucrative practice for these physicians in stormy
regions, but for the victims themsclves there is only incrcasing
ill health unless they seek a non-stormy climate.
Respiratory infections are the major producers of ill health
in stormy regions. Unfortunately the medical profession has little
real help to offer by way of prevention. Drug therapy in pneu-
monia has made great strides toward conquering the terrors of
this disease in the last few years, but colds, sinusitis, chronic
bronchitis, and bronchiectasis are still about as stubborn as ever.
Migration away from storms offers the only real help for people
so afflicted.
While the South-west provides unique health advantages in
its freedom from cycionic storminess, the region is handicapped
by its barrenness and cannot support a dense population. A
realistic public-health policy could soon remedy this handicap
by proper use of mountain water supplies for irrigation purposes
and for the generation of electric power to turn the wheels of
7i
new industries. A few good steps have already been taken in
this direction, but far more must be done before a means of
livelihood can be found for more than a small part of the afflicted
people who would benefit by migration from stormy regions.
chapter 9
TUBERCULOSIS, LEPROSY, AND RHEUMATIG
INFECTIONS
Although energetic people of temperate-zone
climates enjoy winter vacations in warmer surroundings, the
change in environment may have certain bad effects which
should be carefully taken into account. One of our industrial
leaders, wintering in Florida a few years ago, was suddenly
called back to Cincinnati to meet an unexpected financial crisis.
At seventy he was still a vigorous man, active in business and
civic affairs. A few days after his arrival here, however, he
contracted a cold which went on to fatal pneumonia. The
months of Southern warmth had sapped his vitality and left him
unprepared for the respiratory hazards of northern winters.
Although he had been a heavy contributor to the city’s medical
activities, the medical profession could do little for him. Present
effective methods of Chemical and serum treatment were un-
developed at that time.
His death emphasized the dangers people encounter in
changing suddenly from a warm climate to the stormy cold of
northern winters. It is quite common for acute respiratory
infections—colds, sinusitis, bronchitis, or pneumonia—to attack
persons who come north after having become adapted to tropical
warmth. One or two weeks of winter vacation in the south have
little softening effect, but with a stay of a month or more the
body’s vitality declines and resistanqe to infection is sharply
lowered.
During the first week of our return from Panama late in
March, all three of us contracted colds in the raw spring weather.
We had enjoyed excellent health in the south, but two months
of tropical warmth had lowered our resistance. This loss should
be an important consideration for those 'who winter in the
south or who spend a longer time in the tropics. A return to
cooler climates should be made during the summer, so that the
72
body can gradually become accustomed to cold as temperatures
drop through the autumn months.
-
The fall in tissue vitality which takes place in tropical heat is
an element of especially great importance in one of the world’s
greatest scourges, tuberculosis. No victim of this disease, no
matter how inactive it may be at the time, should plan a stay in
the tropics. Tuberculosis there progresses rapidly and may easily
be fatal unless the person is removed to cooler regions. In the
Philippine lowlands, for instance, the tuberculosis death rate is
extremely § high—cases are numerous and resistance is low.
Hospitalization in a sanatorium does patients little good and
merely decreases their chances of spreading the disease. But if
they are taken into the cool mountains, they wage a much better
fight. The resulting improvement is soon lost, however, if they
return again to the lowland heat.
Most physicians in the tropics now appreciate the importance
of this lowered vitality in hot climates and send their patients
out to more invigorating regions as soon as tuberculosis is de-
tected. But the wise doctor will take care that this move does
not plunge his patiënt into the respiratory hazards of winter cold
and storms. Here again the dry non-stormy South-west offers
the region of choice.
To-day many physicians in the northern States feel that
tuberculosis can be handled just as well in the home region as
in the South-west—and so it can be if the patiënt is carefully
guarded against the possibility of acute respiratory infections.
Each cold he contracts, however, is likely to aggravate his
tuberculosis. Northern coolness heightens his general nutrition
and vitality, but the frequent storms which accompany this
coolness add greatly to the dangers of respiratory infections and
more than offset any advantage. Contrary to the belief of some
physicians, therefore, the safest course would still seem to be
migration to the South-west, away from the disturbing storms.
Furthermore, location there should be at altitudes high enough
to afford freedom from severe summer heat.
These findings have important implications for the medical
examination of American troops selected for tropical fighting.
Army and Navy physicians have been carefully X-raying
recruits’ chests to detect incipient or active tuberculosis, but
special attention should be given to divisions slated for future
duty in Affica and other hot climates, where the disease would
thrive. Native troops, on the other hand, are best fitted for
fighting in surroundings to which they have been accustomed
from birth—aswas emphasized by bitter experiences of the last war.
73
From 1914 to 1918 tuberculosis became a terribly fatal disease
among native troops from northern Africa during the winter
months of trench fighting in the mud of France. These men were
ill adapted to the wet and cold of northern France. They showed
little ability to fight the infection. Three months of high fever
and rapid tissue destruction almost inevitably led to an early
death, whereas among French, British, and American soldiers
the disease followed a slower and less fatal course. Pneumonia,
too, and all the other acute infections of the air passages struck
with special fury among the tropical troops fighting or serving
in France during the last war.
A few years ago I decided to investigate the influence place
of birth might have on the ability to fight tuberculosis around
Cincinnati. Large numbers of our people—both coloured and
white—came from the Southern States, while we also have many
immigrants from Europe. Our large tuberculosis sanitorium on
the outskirts of the city cares for the indigent tubercular members
of the population. In going over some three thousand records
of patients who died in this institution, I found a striking differ-
ence between those of northern and those of Southern birth in
their respective abilities to fight the infection.
The disease—from first symptoms to death—had an average
duration of nine months among Negroes from the Gulf States,
while among Cincinnati coloured people it lasted eighteen
months.* White migrants from the Gulf States endured tuber-
culosis for an average of eleven months, but northern-born
whites held out twice as long. Like the Gulf-state group, emi-
grants from Mediterranean countries also survived only about
eleven months, while those coming from countries north or
west of the Alps lasted twenty-two months. These statistics
dealt only with sanitorium deaths from tuberculosis. If we could
follow up patients discharged from the institution, we would
probably find an even greater difference in the ability to survive.
We should remember, too, that these figures include only
tuberculosis among Cincinnati’s poor, in whom the disease runs
its most rapid course. People of higher economie level and
better nutritional state naturally have much stronger resistance,
and their chances of final recovery are much greater. During
peacetime body resistance to tuberculosis has been increasing
in the United States. Even while the country’s sanatoria and
clinics have remained jammed with patients and carried long
waiting lists, death rates have been falfing.
Although the disease continues unchecked as a terrible
scourge among tropical people, it is being brought under control
74
in middle temperate regions and the ultimate conquest is almost
in sight. Freshmen are given tubercuiin tests as a routine in
most colleges, and the number of positive reactions is declining
each year. A positive tubercuiin reaction means that at some
time germs grew in the individual’s body, although they may
all be dead and the person entirely well at the time of the test.
Even fifteen or twenty years ago a majority of the students gave
positive tests, indicating that they had at some time been in-
fected, but to-day relatively few positives are found among
northem college freshmen.
Tuberculosis is also a most deadly disease among tropical
dairy herds, making the production of safe milk a difficult job
in most tropical lowlands. But in the northern United States the
herds are becoming even more free of the disease than human
beings are. This is due largely to the practice of killing all
infected cows, but better feeding and care may also have in-
creased the herds’ resistance.
Although tuberculosis in man rarely comes from cattle, it is a
curious fact that the decline in the disease should have taken
place almost simultaneously in both human and bovine beings.
One other possible reason for the almost concurrent decline
might involve the enlightened and strongly enforced measures
to prevent spread of the disease from sick to well individuals.
Most positive tubercuiin reactions among young people to-day
occur in family groups, indicating direct spread of the disease
from one member to another.
There is no specific drug for the treatment of tuberculosis.
The main burden of the battle falls upon the patient’s own
tissues. It is essential, therefore, that the body be provided with
plenty of good food, including the vitamins nccessary for proper
fuel burning in the cells. But good food and vitamins will be of
little help if external warmth keeps the tissue lires blanketed
down to a slow rate of burning. Cool surroundings promote
rapid combustion of food in the cells and a high general vitality.
Therein lies the principal importance of climate for the tubercular
patiënt.
A disease resembling tuberculosis in many ways is leprosy, the
germs of which are so similar to the tubercle bacillus that it
is difficult to teil the two varieties apart under the microscope.
Both microbes may produce almost identical changes in .the
body; in fact, physicians at leper colonies frequently speak of
tuberculoid leprosy. So it should be no surprise that the diseases
both flourish among people living in depressing tropical heat.
Energetic persons of middle temperate regions appear practically
75
immune to leprosy. Among those actually infected the disease
is inactive and non-contagious. There are scores of lepers in
New York and London who come and go freely without trans-
mitting the disease to others.
In 1935 I went without fear into the wards of the old San
Lazaro Hospital in Manila, where the worst cases of leprosy
have been housed for centuries. The old plank flooring was
being replaced in one wing of the building, and I must admit
I had a feeling of uncleanliness as the winds blew into my face
the old dust which had sifted through that floor from past
generations. In a children’s colony just outside Manila I exam-
ined early-stage cases and touched skin lesions without danger
of contracting the infection. Naturally I used the antiseptic
precautions always taken by physicians handling contact diseases.
In tropical heat leprosy is largely transmitted by contact,
particularly among household or family groups where infants
and children are especially susceptible. Colonies in the past
have usually been placed in localities where the disease is worst,
so that the patients would not be too far away from their friends
and relatives and transportation problems would be minimized.
However, I considered it illogical to keep these unfortunate
victims in the very climatic conditions which so rapidly promote
and spread the disease—especially when we know that it tends
to become inactive and non-contagious in cooler regions.
Therefore, as a result of this Philippine trip and subsequent
studies, I recommended that colonies for the segregation of
leprosy patients be established in the most stimulating climates
available rather than in the regions where the disease spreads
most rapidly.
Our own American leper colony should not be kept at Garville,
where the long summers of debilitating Louisiana heat reduce
diseasc-resisting vitality. Instead, it should be moved to the
Dakotas, where climatic stimulation is high and physical vigour
at its peak. Since no specific leprosy cure has as yet been found,
it would seem reasonable to give northem coolness a fair trial.
Patients brought to the Dakotas would need careful protection
from respiratory hazards during their first winter, but after that
the climate’s effect should be allowed full sway. Perhaps some
day this suggestion will be carried out. Certainly little progress
is now being made to lessen the inroads of this disease among
tropical people.
In stormy climates the rheumatic ills rank next after respira-
tory infcctions as causes of ill health. They are even more closely
related to storm changes than are tuberculosis and sinusitis,
76
and consequendy migration to non-stormy climates is cspecially
imperative.
A young physician with rheumatic arthritis recently visited
me to discuss where he could practise medicine with a
minimum of discomfort from his affliction. He had developed
the infection in both ankles during his intern year at the hospital
and had just suffered his first known rheumatic attack. But his
heart valves showed old damage which had probably occurred
during childhood at some period before repeated sore throats
had necessitated removal of his tonsils. He had spent most of his
life in northem Ohio, amid the cold and storms so conducive
to rheumatic troubles. Having finished his medical course and
internship, he now wished to apply to his own personal problem
some of the climatic information he had heard me explain
during my rounds of the hospital wards.
Except for the slight rheumatic infection in his ankles and the
old damage to his heart valves, this young doctor was apparently
healthy. We discussed the dangerous effects of storminess,
especially during the winter months, and the likelihood of
repeated rheumatic attacks if he continued living in the northern
United States. I recalled how some years ago groups of rheumatic
fever patients were sent from the North Atlantic States for several
months of rest in Puerto Rico. As a result of this step thcir
condition improved considerably. They still had periods of
flare-up in the infection, however, although the recurrcnccs
were by no rtleans as frequent or severe as those in the north.
Patients sent to the non-stormy South-west, on the othcr hand,
have practically no new outbreaks of trouble. Instead, the
damage to their joints and hearts gradually repairs itself.
After considering such cases, I strongly advised the young
man to migrate to the South-west, preferably somcwhere within
200 miles of the Mexican border between El Paso and San
Diego. Because of his damaged heart valves, I also recommended
that he select some branch of medicine requiring relatively
little physical strain. He was already interested in becoming an
eye specialist and I assured him that this type of practice would
not draw too much upon his limited physical resources. But an
eye specialist—or almost any specialist, for that matter—cannot
make a respectable living in rural sections or small towns without
also branching into other lines of practice. This the young doctor
could not do, so his choice of location was limited to Los Angeles
or San Diego, as in the case of the clothing manufacturer with
chronic sinusitis.
Even if no attack of acute arthritis had occurred and focused
77
this young physician’s attention on his rheumatic state, the old
heart damage should have been sufficiënt reason for a change in
residence. Heart damage from rheumatic inïection in childhood
may apparently heal and remain quiet for many years, only to
reappear years later as the result of some other infection or
circumstance which lowers the person’s vitality. Only recently
one of Cincinnati’s leading physician’s—also a faculty colleague
in the medical school—was stricken by such a reappearance of
old rheumatic vegetations on his heart valves and died a few
weeks later. Some years ago a similar fate struck another of our
medical school professors who had devoted his life to medical
research and teaching, but had done so in one of the world’s
worst regions for the rheumatic heart trouble he had carried
since youth.
“Physician, hcal thysclf” may be good advice, but it is seldom
applied. Yet the future secms more encouraging because present-
day physicians are beginning to apply their knowledge to their
own health problems. The more they do this, the more certain
it is that they will pass the benefits of climatic findings on to
their patients. I have received inquiries from physicians through-
out the country who want to know how modern knowledge of
climate could be brought to bear in solving their personal
health problems. It is no small matter for a doctor to give up an
established practice and move to a new region where he must
begin all over again. The fact that physicians now think along
these lines means that they really are coming to appreciate the
important part climate plays in health.
One physician in northern Illinois who was troubled with
sinusitis and high blood pressure asked me which would be best
as a new home site: St. Louis, Seattle, or Houston (Texas). I
assured him that a change to either St. Louis or Seattle would
bring little help. But Houston, I continued, would be an im-
provement, since its warm weather would definitely bring about
a gradual lowering of blood pressure. As for the doctor’s sinusitis,
Houston, while by no means an ideal spot, is less stormy than
St. Louis or Seattle and would have the least irritating effect on
this condition. Incidentally, I emphasized the greater advantages
of the South-west, and at last report the physician seemed
inclined toward Houston.
A Wyoming doctor in his middle forties also wrote for advice.
He was much concerned over the great number of breakdowns
he had been witnessing among men of his age and hoped that
he could escape a similar fate by strategical migration. Since
he had no respiratory or rheumatic troubles, but only a growing
78
tendency toward high blood pressure, I suggested that he seek
the relaxing warmth of Southern Florida. No word has come
as to his final decision.
Every patiënt I see with active rheumatic infection or old
damage to the heart is strongly advised to migrate permanently
to the non-stormy climate of the South-west. Many of them find
it economically impossible to make the move, and bthers lack
the courage for so radical a step. The matter is of greatest im-
portance for rheumatic children. With them it often means the
difference between a healthy and useful life in that beneficial
climate and one of increasing disability in northern cold and
storminess.
Rheumatic infections are far more common and destructive
among poor people, probably because they live on a lower
nutritional level and are less able to protect themselves against
weather changes with adequate clothing and housing. People
of means can afford to send a rheumatic child to a better climate.
The poor, however, cannot make such a move, and the child is
left to grow up in a climate where it is likely to become an
invalid requiring expensive hospitalization on community funds.
In these days of free spending for public welfare, it would
therefore seem wise that steps be taken to insure proper care of
those afflicted with rheumatic infections. Communities should
be set up in the South-west to give them convalescent care and
the chance to again become self-supporting members of society.
The cost would probably be little more than the total now spent
for repeated hospitalization and medical care at home. Time
after time I see young rheumatic patients in the charity wards
of the hospital who most urgently need to get away from the
storminess of Cincinnati winters; yet they are bound by the iron
chains of poverty to the very climate which is worst for them.
An attractive young woman recently came to the hospital
compiaining of acute rheumatic pain and swelling of several
joints. Two weeks previously she had contracted a summer cold,
and less than two days later her joints had become involved.
This reawakening of old joint trouble by a recent respiratory
infection is an extremely frequent occurrence. The young woman
had contracted rheumatic trouble early in childhood, during
repeated attacks of tonsillitis, and had suffered many recurrences
of acute rheumatic fever, with marked damage to her heart
valves. By careful living she had been able to grow to maturity,
marry, and give birth to one child. She had almost died of heart
failure during childbirth, had been warned against future
pregnancies—and, of course, was taught the proper technique
79
-
79
for avoiding them. All stimulants which might increase the load
on her damaged heart—such as cofFee, tea, and cola beverages—
had been removed from her life. In fact all she had left was an
existence of minimal activity permanently overshadowed by the
likelihood of renewed acute joint troubles.
Bom and raised in Cincinnati, she was compelled by poverty
to remain in a climate particularly bad for rheumatic patients.
Her husband, a semi-skilled factory worker, was unemployed
for most of the recent prolonged depression. During the present
rearmament activity, however, even semi-skilled labour is in
great demand, so I urged that he seek employment in some
defence industry located in the Los Angeles area of the South-
west. Permanent migration away from cold and storms offers
this young woman her only hope of relief from further damaging
rheumatic attacks. Her leaky heart valves can never be repaired,
but she could live a useful life if she were freed from attacks of
new infcction every few months. Let us hope that some day
steps will be taken to give such patients the benefits of migration.
Rheumatic and respiratory infections probably produce more
disability in the stormy middle temperate regions than all other
diseases combined. It would be well for people living in these
regions to appreciate what storminess means to them in terms
of ill hcalth. Usually affliction is endured blindly year after year,
without the knowledge that good health might be enjoyed
elsewhere. Migration, to be most effective, should be permanent
and not merely for a brief period of improvemtnt. Even with the
complete recovery possible in the South-west, old troubles are
likely to reappear if the person returns to stormy regions.
CHAPTER io
GANCER
Few people consider climate a determining factor
in cancer occurrence, but recent studies have strongly hinted
that the linkage may be fully as close as it is with heart failure
and the breakdown diseases. Cancer is becoming more frequent
and coming at ever earlier ages in those same regions of the
earth which show in other ways the most severe evidences of
bodily stress. Animals in our experimental chambers have also
indicated that climate may indeed be a factor of major im-
80
portance in determining the frequency and killing speed of this
disease which takes the lives of more than 156,000 Americans
a year.
Cancer occurs about as frequently in mice as in human beings.
Through the years of our hot- and cold-room studies thousands
of laboratory mice have been under observation for varying
periods of time. Between 10 and 12 per cent. of the adults dying
in the cold room developed cancer before death, while in the hot
room not a single tumour was seen. This coincided so well with
the high human cancer rate in cool climates that I decided, to
study the matter more closeiy on certain strains of mice known
to have an extremely high rate of cancer development. Some
cancers in mice seem to be rather strongly hereditary, and in
certain laboratories tumour incidence has been greatly increased
by inbreeding, mating together the offspring of cancerous
parents.
One such strain of mice has been bred to show a high incidence
of breast cancer, over half of the females developing tumours
before death. Two hundred females of this strain were purchased
soon after weaning age and divided into three groups. One
group of 67 was placed in the cold room at 65° F., another 67
were put into the hot room at 910 F., while the remaining 66
were kept under the more variable conditions ordinariiy pre-
vailing in the outside laboratory air. Close watch was kept for
tumour appearance during the next eighteen months. The usual
lifetime of a mouse is about two years, and we had intended
continuing our observations until the mice died of old age.
Failure of the controlling device in the hot room one night,
however, allowed the temperature to rise too high and caused
the death of all in that group when they were about twenty
months of age—but not before they had given us very valuable
information on cancer development.
By twenty months of age 14 of the cold-room group had
developed tumours, while only 4 in the hot room had. The first
mass appeared in a nine-month-old mouse in the cold room.
In the hot room not a single case was found until fifteen months
had passed. Tumours grew almost twice as fast among the cold-
room animals as among the hot-room group and took only half
as long to kill the mice after they were first observed. The first
mouse to die of cancer in the cold room was only ten months old.
The first such death in the hot room occurred at almost nineteen
months. The group kept under the variable laboratory conditions
developed almost as many tumours as were found in the cold
room (13 v. 14), but the masses appeared slightly later and grew
Öi
less rapidly. On examination of all the mice at death, 9 intemal
tumours were found in addition to those of the breast which could
readily be feit before death. These 9 other tumours were dis-
tributed 4 to the cold room, 4 to the control group out in the
laboratory, and only one in the hot room.
These interesting mouse findings are now being checked by
lifetime observations on other groups subject to different types
of cancer. Although final figures are not yet available on the
new groups, it is noteworthy that so far 28 have developed
tumours in the cold room as compared to only 9 in the heat.
The first cold-room mouse to develop tumour did so when 6
months old, while in the heat the first tumour came at 10 months.
None of the hot-room mice of this series have developed more
than one tumour mass, but in the cold room 6 have had 2 or 3
masses appear in different parts of the breast tissue. It would
sccm that the invigorating effect of easy heat loss quickens the
metabolism of cancer cells as much as it does that of normal body
tissues. If this is true, then cancer must be classed along with the
breakdown diseases which received so much attention in an
carlier chapter.
Cancers in human populations are suppressed in tropical heat
almost to the same marked degree we found with our mouse
tumours in the hot room. Cancer death rates along the Gulf of
Mexico are much lower than in the upper Mississippi Valley,
except for cancers of the skin. For some reason tumours of the
skin and mouth are more common in the South than in the
North, perhaps because of irritating effects of the more intense
sunlight. Most other forms occur with greater frequency among
people of the North.
Our laboratory mice also develop skin tumours more readily
in heat than in cold. Painting their skin with cancer-producing
substance from coal tar leads to an earlier production of cancer
in the heat. These tumours grow more rapidly and kill the
animal earlier than in the cold. Live cancer cells injected just
under the skin also develop into fatal tumours more quickly in
hot-room mice. This does not happen when the cancer cells or
irritating Chemical are injected into the deeper tissues. It seems
likely that the richer blood supply going to the skin to facilitate
loss of body heat in hot environments gives such skin a more
active metabolism and renders it more susceptible to cancer.
Human hair grows fastest in hot weather—men must shave
oftener.
Cancer is largely a disease of the later decades of life. From 45
years onward its frequency rises rapidly to old age. Since fewer
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people survive infectious diseases to reach old age in the warmer
regions, it was thought that this might account for the lower
cancer death rate in the South. Closer study of death statistics,
however, showed that the rate among those living in each age
decade rosé much faster in the North and was 50 per cent.
higher among the aged in the North than in the South.
No one yet knows exactly why cancer is more frequent in one
climate than in another—nor indeed what causes it in any
climate. Early operation and radiation therapy have so far
offered the only real hope of cure and then only when the
tumour is in an accessible location. All too common now as a
cause of death, the disease is certain to become even more
frequent as the percentage of older persons increases in the
American population. To-day there are only about 8 or 9 million
persons 65 years of age or over, but this group will probably have
swelled to about 22 million in the United States by 1980—and
that means hundreds of thousands more cancer cases. Educa-
tional campaigns have made people more cancer-conscious and
caused them to seek medical aid earlier than previously. Thou-
sands of lives are saved by the earlier operation of breast tumours,
but the general cancer death rate continues its uninterrupted
rise.
As scientists delve more deeply into ways of causing and
curing cancer in animals, they may find methods for its control
in man. Certain coal-tar products are particularly prone to start
cancer developments in animals, which suggests the possibility
that the combustion products of coal and oil poured out to
contaminate the air of temperate-zone industrial centres may be
responsible for the present rapid increase in the number of lung
tumours. Two decades ago cancer of the lungs was relatively
rare in America; to-day it has become the most frequent type
of cancer among city males of low-income groups. This form of
the disease, together with cancers of other tissues coming into
direct contact with the air breathed or nasal mucus swallowed,
contributes the great majority of such deaths among men of the
poorer classes. Among women cancers of the uterus and breast
still predominate.
Dr. Oughterson of Yale University has recently presented
statistics which hint strongly that some air impurity may be
inciting cancer of the respiratory and upper digestive tract.
On going over death records of the last ten years in the New
Haven General Hospital, he found that cancer of these tissues
was several times more frequent among men on the charity
wards than among private-room patients. It was aiso several
83
times more frequent in men than in women. The difference in
tumour incidence between charity and private patients or
between men and women was less for tumours of the small
intestines, while cancer of the large bowel or rectum was present
equally in all groups. Cancers of the breast were also equally
prevalent in women of the charity and private-patient groups.
These New Haven findings indicate that some cancer-
producing substance is being taken in through the nose and
mouth, affecting the poorer classes more strongly than those of
higher economie groups and men more then women. This
substance must be in the air we breathe, since it involves tumours
of the lungs just as much as it does those of the mouth, throat
and stomach. It fails, however, to affect the most distant parts
of the digestive tract or breast cancer in women.
The finger of suspicion must therefore point to some con-
taminating material in the outdoor air of the city slums, since it
is the poor man who is most affected; and we naturally think
at once of the soft-coal combustion products which usually hang
more densely over city slums than over better residential suburbs.
The New Haven figures should be checked by similar studies
in other cities and among rural residents. Perhaps there is much
more to the city smoke problem than its aesthetic and economie
aspects.
Interest in the contaminated atmosphere of city slums is
further justified by cancer studies on animals. The most active
cancer-producing substances so far known have been obtained
from coal tars. Injections of mere tracés of these substances—
called carcinogens—produce malignant tumours in susceptible
strains of mice, the kind of tumour being determined largely
by the type of tissue cell irritated by the injected material.
Skin tumours follow their repeated application to the skin, lung
tumours follow their continued inhalation of dust particles, and
other kinds of tumours their injection into still other body tissues.
Investigators working with carcinogens take just as great care to
avoid contaminating their own tissues with the materials as they
do with cultures of the most deadly bacteria. Watching mice
develop the cancer masses and die within a few weeks tends to
make the observers cautious. Microscopically and in other ways,
these ' experimental tumours are similar to those occurring
spontaneously in human beings.
Late in the last century it first became known that coal tars
were capable of causing cancer when the London chimney
sweeps were found to be unduly afflicted with cancers of the
skin. Still later physicians observed that men employed around
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gas-manufactueing plants or handling coal tar in various forms
were also subject to frequent skin cancer. Tars from soft coals
which contain much volatile matter seemed most liable to
induce these tumours, although the coal itself was quite harmless.
Miners usually have little cancer, except in certain European
mines containing radioactive ore, where more than half the
miners died of lung cancers before proper safety precautions were
finally instituted.
Recent intensive studies have given us much Information
about cancer-producing fractions of coal tar and about some of
the avenues through which they may reach our bodies. Labourers
coming in direct contact with tar in their work are not the only
victims. Dust particles swept up from tarred roads contain these
substances, as do also the dust particles polluting the air of the
industrial cities in our energetic northern climates. They can
readily be extracted from the soft-coal soot in our chimneys.
They volatilize at the firebox temperatures prevailing when soft
coals burn with heavy smoke production and pass off with other
flue gases. As the gases cool down in the chimney, coal-tar
compounds condense on carbon soot and ash particles and are
thus carried out into the city air. It is the coal tar on soot which
makes it smear so readily and produce the stains so difficult to
wash off.
Medical scientists and cancer investigators are not yet ready
to say that soft-coal smoke is an important factor in the sharply
increasing occurrence of lung cancer in our city slums. But the
suspicion that such may be the case is rapidly gaining ground.
Direct linkage of any such serious health menace to soft-coal
smoke would pave the way for speedy clearance of the smoke
from our city atmospheres.
CHAPTER I I
SHADOWS OVER OUR CITIES
The atmosphere-darkening shrouds of dust and
smoke which hang above so many American cities have often
been the subject for a peculiar sort of optimism. In the past
people have pointed to the man-made shadows with national
pride, saying that the darkness was a sign of prosperity and
industrial activity. To-day the fumes pouring forth from United
States factories indicate that the greatest war effort in history
is hitting on all cylinders, but the darkening pall over our
cities brings with it serious heaith hazards of major proportions.
The picture is darker than the thick smoke clouds themselves.
It is a story of increased and increasing disease.
Natural climates are not the only ones affecting human heaith.
Man himself, by widespread burning of soft coal in industrialized
areas, has brought about local climatic conditions loaded with
the most vicious and dangerous heaith aspects. Great publicity
was given some months ago to the effective blackout of a large
industrial plant in the Mid-west by a few switch engines spraying
a tarry preparation on to the hot coals in their fireboxes. This
method of blackout could indeed well be used for daytime
concealment from bombing planes. It needed no special demon-
stration, however, for such blackouts have long been the winter
curse of our soft-coal-burning industrial cities. But the evil effects
of smoke on heaith, as revealed by some studies I have recently
made in Cincinnati and Pittsburgh, raise the question whether
such blackout for wartime use would not be even more deadly
for a city than the bombing it was intended to prevent.
A truly devastating respiratory disease situation has been
found to exist in the “bottoms” districts of Cincinnati and
Pittsburgh, whcre crowded humanity lives alongside factories
and switch engines which keep the atmosphere heavily polluted
with their flue products. Many other cities fare just as badly,
although the price they pay has not yet been investigated. St.
Louis faced a particularly vicious situation with her cheap
high-sulphur coal- from the nearby Illinois fields. There were
times when the sulphur gases in her “smoggy” atmosphere
became really choking to breathe. She has now passed two
winters under a stringent anti-smoke ordinance, and most of
her citizens are enthusiastic about the improvement already
accomplished. Pittsburgh followed suit with a similar regulation,
but heavy war-industry demands for all kinds of fuel has made
enforcement impossible until peacetime conditions return.
Other cities—Cincinnati among them—were giving the
subject active consideration when the war with Japan broke
out. Here in Cincinnati I had been asked to serve on a com-
mittee looking into the local smoke situation, with a view to the
passage by city council of an effective anti-smoke ordinance.
This had necessitated my active interest in the subject and soon
brought to me a realization that very little was known regarding
smoke’s harmful effects upon heaith. Some study had been given
the matter in the Ruhr Valley of Germany and in our own
-
86
Pittsburgh, but the published findings were only of a general
nature and inconclusive. *
I therefore decided to see what specific evidences of harm I
could find in Cincinnati and Pittsburgh, choosing these two cities
for two reasons. Each has good soot-fall and death-rate data by
census tracts or soot-fall districts over a number of years, and
each has a local topography which presents sharp contrasts in
smoke density. Pollution is severe in the low-lying bottoms
districts of both cities and is relatively mild in their hilltop
suburbs, especially those situated to the west of the industrial
sections. The facts unearthed in this study leave no doubt of
smoke’s evil effects. The respiratory disease situation thus
uncovered is severe enough to demand vigorous action regardless
of cost as soon as the war emergency and coal shortage have
passed.
The threat is illustrated by the case of a friend of mine from
New York who recently stopped for a few days in Cincinnati on
his way to the South-west. The weather happened to be lowering,
with little movement in the muggy air—the kind that keeps our
smoke as a heavy blanket over the low-lying basin area of the
city. My friend developed an extremely severe respiratory
infection and frantically called for me by telephone from one
of the hotels down under the smoke. (The incident happened
just at a time when I was out seeking for evidences of its effect
upon the city’s population.) Unable to find me, he finally called
another physician, who sent him to a hilltop hospital.
This man claimed that he was always affected in this fashion
if he stopped in Cincinnati during the winter season, and he was
convinced that the smoke was responsible. This time he came
very near to pneumonia, with considcrable fever and acute
inflammation well down in the smaller air passages. Treatment
with the newer Chemicals which have proved so effective in
pneumococcic infections soon made him well again, but the
experience has only deepened his conviction that our city* smoke
is dangerous.
Smoke’s chief effects are naturally upon tissues of the respira-
tory system, from nose to lungs, for these are the body surfaces
brought into most intimate contact with the dirty air. My
search for harmful effects thus centred around pneumonia,
tuberculosis, and lung cancer, since these are the respiratory
diseases which kill and leave death records for study. Information
on sinusitis, bronchitis, and colds would be even more interesting,
but these milder diseases rarely kill and no records of their
incidence are available.
87
The pneumonia situation is most striking in its relation to
smoke, so let’s look atit first. My New York friend was indeed
fortunate to have escaped pneumonia, for it strikes with great
frequency each winter among people living in the dirty air of
our congested industrial districts. During 1937 and 1938 in
Gincinnati there were 480 pneumonia deaths among 178,000
residents of our low-lying census tracts and only 160 among
277,000 people of the hültop suburbs! Three-quarters of the
city’s pneumonia deaths in only a little over a third of its
population!
This was at first thought to be due to overcrowding in the
basin area where family incomes are lowest. Pneumonia is a
contagious disease, it is true, and overcrowding does tend to
spread it from one victim to the next. But this does not explain
why the men in these areas should have almost three times as
much pneumonia as do the women living alongside them!
In the cleaner suburban districts men have only Slightly more
(5 per cent.) pneumonia than their wives, but as smoke pollution
increases, the male rate rises much faster than the female. In
the dirtiest sections the men have three to five times as much
pneumonia as the women!
This greater pneumonia hazard of the city labourer cannot
be due to his outdoor exposure to chilling, for men on Ohio’s
farms have only 5 per cent. more pneumonia than their wives
(just as in the clean city suburbs). Nor can it be a result of their
low economie status and faulty diet, for men are usually better
nourished than their wives. The only reasonable conclusion left
is that the high rate is due to the outdoor smoke-laden atmos-
phere in which the men as a rule spend the most time. Those
remaining indoors do not escape entirely but they are much
less affected.
In both Gincinnati and Pittsburgh the railroads enter largely
along valley routes, and industrial plants have naturally located
along the railroads. Major use of soft coal thus takes place in the
low-lying districts, and on days of little air motion the smoke
from these sources hangs suspended in the valley sections. In
both cities the pneumonia death rates fall rapidly with each
hundred feet of ascent up from the valley bottoms. The death
rate is three to ten times higher in the dirty basin districts than
out in the cleaner air of the suburbs.
Tuberculosis deaths are also far more common in the most
smoky parts of the city. The rates are many times higher than
out in the clean suburban air and are markedly higher for men
than for women. Negroes, many of whom have migrated from
88
the South, cohgregate mainly in these dirty districts and have
tuberculosis and pneumonia death rates twice as high as the top
rates of the white population. Regardless of race, any group
migrating from Southern States will be far more susceptible to
respiratory infection than will native northerners, but these
migrants are particularly unfortunate when they settle in our
most polluted districts.
The distribution of soot-fall (both carbon particles and fly
ash) in various parts of the city bears a direct relation to pneu-
monia and tuberculosis deaths: The very districts having most
excessive soot-fall are the ones with highest respiratory death
rates, while in the cleanest suburban areas such deaths are
quite negligible in number.
Most of the city’s lung cancers also develop in these same
dirty basin districts, people there being about three times more
likely to develop the disease than are suburban residents. This
form of cancer, too, is several times more frequent in men than
in women. That the non-contagious, non-infectious lung disease
should show the same relation to soot-fall as do tuberculosis and
pneumonia is strongly suggestive that air pollution may be the
damaging factor. That men, who are out in the dirty air much
more than women, should be so much more afflicted with all
three of the lung diseases only adds to the suspicion that air
pollution is largely responsible for these hcalth hazards of dirty
districts.
In presenting these findings, I do not intend to belittle the
evil effects of overcrowding, poverty, and malnutrition which
are so prevalent in our basin districts. The harmful effects of
smoke are only added to these other hazards which confront
the unfortunate residents of polluted regions. It is difficult to
assess accurately the relative importance of the various health
handicaps they face, but air pollution is probably responsible
for many respiratory illnesses than all other factors combined.
Since respiratory troubles are by far the most frequent causes of
ill health among people of temperate regions, it would scem
imperative that steps be taken to eliminate the smoke hazard
which so severely intensifies this type of illness in our polluted
urban districts. Urgency is dictated not only by common human
impulses, but also by a realization of the tremendous loss of man-
hours among workers in war industries who are stricken by the
smoky excrements of their own factories.
Perhaps most city residents have given*little thought to just
what materials they are taking in with the air they breathe.
The black smoke you see is largely carbon, and you have probably
89
been told that carbon is harmless—may indeed'be beneficia!.
It is harmless if it is pure carbon, but that issuing from smoky
chimneys is far from pure. Coal-tar compounds in soft coal are
also liberated as gases under the same furnace conditions which
produce the black smoke. As these gases cool in the upper
chimney, they condense on the carbon and ash particles present
in the smoke and are thus carried out over the city. Soft-coal
soot from the chimneys of English homes has been found to be
almost half coal tar in some instances. High-volatile coals
liberate the largest amounts of both soot and coal tar when im-
properly fired; if burned smokelessly, then both tar and carbon
are consumed in the firebox. These tarry substances which
condense on smoke particles contain the cancer-producing
Chemicals used in experimental cancer studies and are coming
to be seriously suspected as a possible cause for the lung cancer
increase among the people of our city slums.
Along with the carbon in smoke goes a considerable amount
of so-called “fly ash” composed of much the same sort of silicate
compounds which killed so many hundreds of tunnel and quarry
workers exposed to the fine rock dust produced in blasting
operations. It was formerly thought that these particles irritated
the lungs because of their sharp cutting edges, but now their
action is considered to be a Chemical rather than a physical
irritation. Before proper precautions were instituted, these
particles produced deadly silicosis among tunnel workers. But
the ailment is seldom seen among city residents exposed to fly
ash. It is possible that a lower grade of irritation may be respon-
sible for their increased susceptibility to respiratory troubles.
Similar fly-ash irritation in the nasal sinuses probably plays a
large part in the prevalence of sinusitis among dwellers in our
coal-burning cities. One might expect suburban residents who
work daily in the downtown basin area to be affected almost as
much as the basin “natives.” Most of these people, however,
work in indoor atmospheres which are much less polluted and
sleep at night under cleaner air conditions.
Carbon soot has been decreasing in recent years, because more
factories and homes have installed mechanical stokers and
secured better burning of the cheap grades of soft coal. Atmos-
pheric fly ash, however, is thicker than ever because more violent
mechanical draughts in fireboxes and chimneys have carried larger
proportions of furnace ash out into the air. The great heating
plants of industrial, apartment, and office buildings add to the
fly-ash problem by their nightly blowing-out of the accumulated
material in their stacks. This material should be trapped and
90
removed from below instead of being permitted to escape and
contaminate the sleeping city.
Still another important smoke constituent is the sulphur
which passes off in the form of oxide gases. Sulphur oxides
become highly irritating and corrosive acids when dissolved in
water. It was probably this type of irritation which affected the
noses and air-passage linings of St. Louis residents and, more
than any other factor, inspired that city’s successful anti-smoke
crusade. Coals burned there have a high sulphur content (3-5 per
cent.). At times the atmosphere became really choking from
these fumes. Out-of-towners usually transacted their business
as quickly as possible on such days and then rushed away to less
irritating atmospheres outside the city. Many centres are much
more fortunate in being supplied with coals of lower sulphur
content, but even so there is still enough of these acid fumes to
etch stone buildings and disintegrate outdoor paints and exposed
metal surfaces.
Fly ash, sulphur fumes, and carbon soot loaded with coal tar—
these are the damaging factors in city smoke as far as man himself
is concerned. Cutting off of sunlight is probably the least im-
portant loss, for normal winter cloudiness and the acute angle
at which winter sunlight strikes the earth in Cincinnati make it
necessary for us to get our vitamin D supply from food sources
during the smoky season. Considering the matter from the
respiratory disease standpoint alone, urban residents are fully
justified in taking any steps necessary for abolishing the smoke
pollution evil. Several cities are becoming greatly concerned
over the situation, and as usuai there are economie interests
which oppose the needed changes. A half-century ago
similar objections were raised against plans for purifiction of
city water supplies. It was only the clear-cut demonstration that
typhoid and other enteric fevers from polluted water were killing
thousands each year that forced the acceptance of water purifi-
cation. Similarly, purified city air will probably remain a mere
hope until enough citizens properly appreciate the hcalth
hazards of smoky atmospheres.
If any smoke-abatement programme is to lessen air pollution
hazards, it must consider certain fundamental factors. Carbon
soot and coal-tar compounds flow into city air almost exclusively
as a result of the faulty burning of high-volatile soft coals. Such
coals can be burned smokelessly with proper furnace equipment.
Hence, abatement campaigns are being conducted mainly along
the lines of prohibiting the use of high-volatile soft coals unless
proper equipment is available for burning them without smoke.
9i
Few industrial plants (except for blast-furnace operation) use
any coals except the cheaper, high-volatile types which are
obtainable in' largest quantities. Proper equipment enables these
companies to burn such coals smokelessly and without loss of
unburned fuel through smokestacks. Increasing numbers of
home-owners are also installing efficiënt mechanical stokers for-
these cheap coals. All that is necessary to do away with the black
smoke evil completely is to insist that the rest of the homes and
the railroad engines either burn low-volatile coals or obtain
equipment for the proper handling of the high-volatile varieties.
Relief from black smoke, however, in no way lessons the fly-
ash problem. The ash content of coal is not related to its load
of volatile materials or its tendency to smoke when improperly
burned. In fact hard coals with almost no volatile matter may
yield just as much ash as the high-volatile soft coals. Entirely
separate steps must be taken to clear city atmospheres of fly-ash
hazards. Better settling chambers or traps for the flue ash, or the
use of water sprays to cleanse the chimney gases, will do the trick.
Relief may often be obtained simply by avoiding sudden air
blasts into the firebox. Many types of home stokers have only one
speed for their draught fan, and the sudden air blast as the fan comes
on carries large quantities of fine ash up the chimney. A more
gradual onset of the draught current would remedy this situation.
Washing of flue gases with water sprays would eliminate most
sulphur gases as well as solid soot and ash particles. In fact, this
is practically the only method by which the sulphur oxides could
be removed. Proper firing to eliminate visible smoke will in no
way lessen sulphur-oxide fumes—it might even slightly increase
them by providing for better oxidation of the last tracés of
sulphur in the coal. So St. Louis, even with her stringent anti-
smoke ordinance, may find her atmosphere just as choking and
corrosive as ever unless she compels spray washing of flue gases.
Her water supply would prove quite inadequate for such washing
in all her chimneys, but in the larger coal-burning plants water
could be used over and over again after proper treatment.
The amount of carbon soot deposited over Cincinnati has
been declining in recent years with the increase of stokers and
gas or oil fumaces. Greater use of coke has also helped. However,
fly ash has increased even more than carbon soot has decreased,
so the net health situation is worse instead of better. Evidently
some highly technical consideration must be given to smoke
elimination before genuine relief can be obtained.
One highly vocal objection raised by certain politicians and
economie groups is that nothing should be done which would
9*
increase the financial burden of poor people residing in polluted
districts. To be sure, low-volatile coals and coke cost more than
the high-volatile varieties and are difficult to bum in the make-
shift stoves of slum districts. Newer types of firebox arrange-
ipents, however, will solve that problem; a two-chambered
firebox has been devised in which the coal bums freely on one
side while new coal on the other side is being coked by the heat.
Liberated gases are forced to burn in the flame of the open side.
When new coal is needed, it is placed in the burned-out side and
permitted to coke while the heat-treated coal on the other side
is burning. With such an arrangement, high-volatile coals could
be burned with little smoke in the poorest home.
Lacking storage space for fuel, the poor usually buy their coal
in small lots from hucksters. Hence, fuel costs dearly and high-
volatile coals are usually used which burn most freely in make-
shift stoves. Establishment of city-controlled fuel depots where
these people could obtain their own coal would provide better
fuel for the same money. New-type stoves to burn even high-
volatile coals smokelessly, and with more economical-combustion,
would save enough on two years’ fuel bill to pay for the new
stove. Thus the poor need not suffer. On the contrary, they
would enjoy lower heating costs and, from a health viewpoint,
would gain most from a lessening of the pollution evil.
We have not yet even considered the greatest pollution element
in city air, the element most responsible for lowcred visibility
and winter “smog.” This factor is the steam given off from
industrial power plants and locomotives. Soot-fall over Cincin-
nati is in the neighbourhood of a half million tons a year, while
the railroads alone liberate about ten times that much steam
into the city atmosphere. The steam quickly turns into invisible
water vapour during the summer when the air’s water-holding
capacity is high. Cold winter air holds little water vapour,
however, so all added steam then remains as fog to becloud our
atmosphere.
For several years I tried to find out just how much steam the
railroads actually produced daily in our metropolitan area.
Officials made evasive replies and continually referred my
inquiries from person to person, bringing me to an utter dead-
end as far as information was concerned. But during recent
hearings before a committee attempting to draft a municipal
anti-smoke ordinance, I did obtain the desired information in a
roundabout manner. Upon questioning, the railroad and coal
representatives revealed the approximate amount of coal used
annually by locomotives operating within the Cincinnati
93
-
switching area. This was roughly a million tons a year. Each
pound of coal burned in a steam engine changes 5 to 10 pounds
of boiler water into steam. Using the lower figure of 5 pounds of
steam for each pound of coal, I calculated that the railroads
alone would add enough water daily to our city atmosphere to
give o*6 grains per cubic foot of air over an area of 50 square
miles and extending upward for 300 feet. On windless days the
steam would be held within these approximate bounds under
prevailing topographical conditions.
This 0*6 grains per cubic foot of air is a negligible amount
during summer warmth. Air at 90° F. can hold over 10 grains of
water vapour per cubic foot and is not often over 70 per cent.
saturated except during periods of actual rain. As midday
temperatures drop down below 6o° F. through the autumn
months, however, the air holds less water vapour, and additional
nightly cooling brings it to the saturation point. Engine steam
then begins to remain as visible fog instead of disappearing as
invisible water vapour. Fogs form even in country districts
because of this nocturnal cooling and supersaturation of the air,
but their presence in industrial districts is tremendously in-
tensified by the steam liberated from power sources. Thus, no
matter how thoroughly city dwellers eliminate smoke and fly
ash from the air, they should not expect to have clear winter
atmospheres and good visibility unless the steam problem is
solved.
The situation is particularly acute on windless winter days
when the blanket of industrial and locomotive steam shrouds
lower-lying urban districts, at times even piling up sufficiently
to hide some of the hilltop spburbs. On such days all the flue
products from the city’s fires are held suspended or in solution
by the steam cloud, and we have to breathe this vile mixture—
often for several days at a time. These periods probably play the
most important role in bringing on respiratory diseases and
general ill health. Fly ash and soot quickly settle to the ground
during the summer, leaving the air fairly clear. But during the
cold, still days of winter steam clouds hold in suspension all the
poisonous flue products, giving us the soupy mixture which has
been aptly called “smog” (smoke and fog).
Many large industrial plants use their exhaust steam to heat
their buildings in winter. Others might follow this example or
at least condense the steam to keep it out of city atmospheres.
Just how feasible condensing devices would be for railroad
engines is a matter of which I have little knowledge. Already
railroads are rapidly changing to Diesel power, however, and
94
if the trend continues, steam may become as outmoded as the
horse and buggy. The only other socially beneficial alternative
in heavily populated metropolitan districts is the use of efficiënt
steain condensers or electricity. Use of Diesel or electric loco-
motives would solve both smoke and steam problems so far as the
railfoads are concerned.
For years I have driven from bright suburban sunlight down
into the dense murk of the basin area. And for years I have
wondered how long the people of our American cities would
continue to tolerate such pollution of the air they breathe. At
last they seem really to be awakening to the evils of the foul
artificial climate in which they must live. The drive to produce
materials for the all-important war effort may stimulate further
and faster action by persons who realize that the healthier a
nation is, the bet ter it can fight. The first efforts to cleanse
American urban atmospheres may fall short of the ioo-per-cent.-
effective mark. But only by trial and test will it be possible to
arrivé at a solution of the vital pollution problem. Man may not
be able to control natural weather, but he should be doing a
much better job in straightening up the mess of his own weather-
making.
CHAPTER 12
KILLING HEAT
Northerners encounter still other risks than
those of natural storminess and the man-made smoky
atmospheres over their industrial centres. They are especially
vulnerable to the severe summer heat waves which often settle
over middle latitudes of the United States. The high-metabolism
people of these regions cannot subdue their inner fircs quickly
enough to meet the sudden difficulty{ in heat loss. Thus thousands
of them may develop heatstroke within a few days’ time—and
this at temperatures which would not bother tropical residents
in the least. Heatstroke—in both animals and men—occurs more
frequently in the upper half of the Mississippi River Basin than
anywhere else on earth. Most of the deaths occur during the first
fortnight of a torrid spell, for the body takes about two weeks to
adjust its rate of heat production downwards. After this adapta-
tion has taken place, it can safely stand still higher temperatures.
95
Heat which kills men and animals in June or early July can
usually be endured during August.
All warm-blooded animals protect themselves against excessive
heat almost entirely by increased evaporation of water. Their
bodies normally lose heat in three ways—by direct outward
radiation into the surroundings, by conduction to the air or
other materials in direct contact with the body, and by water
evaporation from the skin or mouth and air passages. The first
two avenues of heat loss can operate to advantage only when
surrounding temperatures are below that of the body. They
are thus of little help on days of severe summer heat when extemal
temperature is higher than that of the skin. In fact, the body may
even be taking up heat through these two avenues, especially if
exposed to the direct radiant heat of the sun. Water evaporation
must therefore bear almost the entire burden of heat loss in
times of real stress.
Water is peculiarly well suited for this purpose. In passing
from liquid to vapour form it takes up enormous quantities of
heat, cooling the surfaces from which it is evaporated. Vaporiza-
tion of a pint of water takes four and a half times more heat than
is required to raise the water from the freezing to the boiling
point. This heat of vaporization is said to go into the latent
form, for it disappears without rise in temperature. About three
quarts of water vaporized per day would be needed for the
average resting person to lose all his heat through this channel.
During physical labour or active exercise the amount required
would be three or four times that much.
When the body’s water-evaporation system cannot meet the
extra demands of hot weather and allows too much heat to
accumulate within the tissue, the result is a dreaded heatstroke.
One of my first experiences with this condition—which strikes
animals as well as men—occurred in the Dakota harvest fields
where I worked as a hand at the age of sixteen. The victim was a
valuable and much-loved horse whose death affected me deeply.
Tom was a light Hambletonian carriage horse with plenty of
fire and sparkle to make life interesting on the road, but during
the busy harvest weeks he had been pressed into service tem-
porarily as a substitute for a sick mare in the six-horse team
pulling the header. This was before the day of tractors or power
farm machinery of any sort. Horse-power on the farm still meant
horses. Through the hot forenoon sun Tom forged well out in
front of his slower teammates, trying to urge them to a faster
pace. Such drudging slowness ill fitted his fiery spirit and willing
heart. About ten o’clock he ceased sweating and in another hour
96
suddenly began to stagger in the hot sun. His owner, riding the
header, had been watching him closely all morning, trying to
hold him back to a slower pace. He had noticed Tom’s glossy
coat changing from wet to dry, but had delayed action until the
horse actually began to collapse. At the first stumble Tom was
quickly unhitched and his harness taken off, but within five
minutes he was prostrate on the ground, and in another half-
hour he was dead.
That heatstroke death of the farm’s favourite pet and most
willing and intelligent servant just about broke the hearts of the
farmer and his wife. Many days passed before they could smile
again. At that time I knew little about the physiological basis of
heatstroke, but experience with human cases in the years since
then has indicated that Tom’s life could have been saved if he
had been plunged promptly into a tank of cold water to take the
fever out of his system. But there he was, completely prostrated
a half-mile away from any water. We poured the little we had
in our jugs over his head and body, but to no avail.
The tragic death of Tom in the Dakota harvest field, was
typical of a danger for which the wise farmer was always on the
lookout. During July and August heat, any horse which ceased
sweating while at work was always carefully watched for further
signs of trouble. A small drainage ditch ran through our Indiana
farm, and we would sometimes dip up water from it to pour over
the horses if they began to be seriously affected by the heat. We
knew there was little danger as long as free sweating continued.
Other farm animals are much more susceptible than horses
to heatstroke, but they are not forced to do hard work out in
the fields under the hot sun. Cattle develop fever quite readily.
They have a much less effective sweating mechanism and like
to stand in water when the weather gets hot. Hogs and chickens
have almost no sweat glands and are quickly prostrated by
excessive heat—as I learned that hot August day when I neglected
to open the feed-lot gate so the shoats could wallow in the mud
through the midday heat. Hogs provide their own heat pro-
tection if any water or mud is available, but chickens or turkeys
like to keep their feathers dry. Their only method of increasing
heat loss from the body on a hot day is by panting, which
quickens the evaporation of water from the mouth and linings
of the air passages.
Even with their efficiënt water-evaporation method of losing
heat, human beings may be affected by the hundreds during
particularly blazing periods. The grim symptoms of heatstroke
are familiar to physicians. The victim first stops sweating, then
Dcüm 97
developes headache and high fever. He soon collapses and be-
comes unconscious, with a rise in blood pressure, full, bounding
pulse, and dry, hot skin. Death often comes quickly—just as it
did to Tom in the harvest field—unless the victims are freed of
the accumulated heat. When a heatstroke patiënt is brought into
the hospital, he is immediately placed in an iced bath and
massaged vigorously until internal temperatures have dropped
almost to the normal level. He is then taken out of the tub and
wrapped in wet blankets to get rid of the last tracés of fever more
slowly. If the massage in the ice-water bath lasts too long, the
body temperature may drop far below normal, bringing on a
condition of shock. Many heatstroke patients died of such shock
before this fact was properly appreciated.
To be most effective, heatstroke treatment must be started
soon after the patiënt has collapsed, and the sooner the better,
for the high internal temperature brings quick damage to vital
body tissues. Any victim should immediately receive the benefit
of whatever cooling facilities are at hand, even though it is
nothing more than dousing with a pail of water and vigorous
fanning to speed evaporation. Such emergency measures, applied
while the victim is being hurried to better cooling facilities,
greatly improve the chances of recovery.
Such attacks are common in parts of the United States. In
early July of 1934 severe heat settled over Cincinnati, St. Louis,
Kansas City, and other population masses living in that portion
of the Mississippi Basin, prostrating many people and actually
killing over five thousand. Two years later heat came in mid-
August and killed relatively few veteran heat sufferers in these
cities. Farther north, however, in Omaha, Minneapolis, Chicago,
Detroit, and other mid-western cities of similar latitude, this
heat was fatal to thousands who were unaccustomed to such
acute difficulty in losing body heat.
During the first week of the 1934 heat I went by automobile
from Cincinnati to Kansas City, passing through the Indiana
and Illinois harvest fields. Horses were dying of heatstroke by
the hundreds, and tales of human prostration greeted me at
every place I stopped. A hush of awe and dread had settled over
the country as the margin between life and death seemed to be
narrowing down to the vanishing point. In Cincinnati, ambu-
lances were busy day and night, bringing prostrated and un-
conscious victims to the hospital for treatment. Body temperatures
of iio° F. were not uncommon, and many victims died before
they could be placed in the iced baths for quick cooling. In the
1936 heat wave we were somewhat better organized to handle
98
the heat cases, with police and hospital ambulances carrying
ice so that the cooling of the victims could begin as soon as they
were picked up.
One man working in the railroad yards became dizzy at one
o’clock on a July aftemoon, feit hot and started to walk home
about an hour later. He collapsed after going four blocks, was
picked up by an ambulance, and became conscious again only
after his body temperature was approaching normal in the iced
bath at the hospital. When he reached the institution at half-past
three his temperature was 109° F. Twenty-five minutes later
in the iced bath it was 102° F. He was then removed from the
tub and wrapped in cold blankets so that the last remnants of
fever could die down at a slower rate. In another forty-five
minutes his temperature was 98.2° and he feit almost normal.
Acute difficulty in losing body heat may affect people in
quite a different way, producing so-called heat exhaustion.
lts onset, less sudden than that of heatstroke, comes with weak-
ness, prostration, lo’w blood pressure, and weak, rapid pulse.
The skin is pale and wet with a clammy perspiration, although
in certain cases there may be some fever. Stomach cramps,
vomiting, and diarrhoea often accompany heat exhaustion and
accentuate the patient’s collapse. To plunge such a person into
a cold bath—as one would a heatstroke victim—might bring on
a fatal shock. What hc needs is stimulation and the application
of warm packs if his temperature is subnormal.
Another common effect of heat is connected with the body’s
water-evaporating efforts to keep cool. Water excreted through
the sweat glands carries out with it considerable quantities of
salt, and people working in hot environments are liable to
become ill simply from loss of too much body salt. Muscle
cramps, weakness, dizziness, prostration, nausea, and vomiting
may occur, with prompt relief when the lost minerals are re-
placed by simply swallowing salt water. This form of severe
heat effect is seen in boiler or furnace rooms, in certain processing
plants where the product requires hot moist air, and among all
workmen doing hard labour under difïicult conditions of heat
loss. Under such circumstances men are now advised to keep
salt tablets handy for use at the first hint of trouble and to drink
salt water instead of regular drinking water. Many offices in
Washington, D.C., which is notorious for its scorching humid
summers, have a handy supply of salt tablets for desperate
employees.
The case of a thirty-year-old coloured foundry employee
illustrates quite well the problem of heat cramps. One sultry
99
June day, while working in the hot foundry environment, he
drank immense amounts of water and cold beverages to make
up for his sweating losses. About noon he vomited and was
seized wth severe cramps in his hands, arms, legs, and abdomen.
Large knots of cramping muscle stood out on his body and
caused excruciating pain. He was taken to the nearby emergency
hospital and given a quart of salt solution—with almost instant
relief. Thousands of industrial workers are now saved simiiar
trouble by keeping salt tablets at hand to eat or dissolve in
drinking water during periods of excessive sweating. As we
might expect from our findings in Chapter IV, some industrial
plants are also finding that equal or better protection may be
afforded by a few milligrams of thiamin (vitamin Bx).
Bathers often suffer from cramps during hot-weather swimming
because of this same body salt loss. Sudden chilling in cold water,
after previous perspiration in the heat, brings on the painful
symptoms. A simiiar cramping tendency of the muscles is also
present during the digestion of meals when large amounts of
salt-containing fluids are being poured into the stomach and
intestines for digestion of the food. That is the scientific basis for
the warning against going in swimming immediately after
mealtime.
But heatstroke is the most common hot-weather threat to
energetic northerners. It is important and interesting to know
that certain groups among the population are more susceptible
than others. Elderly people, especially those with high blood
pressure or hardening of the arteries, are most likely to be
stricken. Difficulty in gctting rid of the body’s waste heat causes
a spceding-up of blood flow from internal organs to the skin, a
process which brings heat to the surface where it can be dissipated
more rapidly. This increased blood flow throws greater work
on the heart and is liable to bring on heart failure in people
whose margin of safety has already been reduced.
Chronic alcoholics are also particularly sensitive to heatstroke.
Many victims reveal a history of habitual drinking, or else
doctors find they had been drinking just before collapsing in the
heat. The relationship between alcohol and heatstroke is probably
due to liquor’s effect upon the brain centres and a disturbance
of the intricate nervous control over the sweating mechanism.
Medical experience indicates that alcoholic drinks should be
avoided or used sparingly during severe heat. Even in the tropics,
where a low combustion rate reduces the danger of heatstroke.
people usually forgo strong alcoholic drinks during midday heat.
One of my friends with several decades of tropical experience
ioo
-
cautions against hearty beer drinking when the body tissues
have been dried out by previous perspiration. To quench one’s
hot-weather thirst with beer is liable to lead 1$ rather profound
intoxication, for the dried-out nervous tissue takes up the alcohol
and water quickly and becomes deadened before the alcohol
can be burned. A normal person will burn the small percentage
of alcohol in beer almost as fast as it can be absorbed into the
blood, and as a result beer intoxication is difficult. But when the
body tissues lose a great deal of water by profuse sweating,
absorption becomes much more rapid and even beer drinking
has its dangers.
One attack of heatstroke or prostration leaves an individual
far more susceptible to similar trouble in subsequent heat
waves. Since doctors have not yet found a way to overcome this
sensitivity, heat victims must take special care to avoid futurc
exposure. Proper intake of the B vitamins in adequate amounts
may protect them against future trouble to a considerable
degree.
City dwellers suffer much more during severe heat waves
than do residents of rural areas. This is largely bccausc the sun’s
daytime heat tends to be stored in the pavements and piled-up
masonry of the crowded buildings faster than it can be given off
at night. Trapped inside the buildings, it causcs indoor tem-
peratures to rise higher with each succeeding day of heat. In
open rural areas cach day’s load of heat is pretty thoroughly
re-radiated into outer space at night. Green vegetation also helps
in lessening the sevority of heat, for it is largely composed of
water which absorbs the heat without much changc of tem-
peraturc. The dry earth of cultivated fields, or the masonry and
pavement materials of the city, become much hotter under the
same intensity of sun’s heat than do growing plants.
Highest daytime temperatures are usually cncountcred in
desert regions, for the sand heats up quickly under the blazing
sun; but it also cools quickly at night as it radiates its daytime
heat off into space. Although tropical regions of heavy rainfall
receive just as much heat, the dense water-laden foliagc on all
sides keeps air temperatures from rising very high; but the
abundance of water everywhere, with its load of stored heat,
also makes the nights warm and oppressive. Tempcratc-zone
cities, with their towering and crowded buildings of concrete
and brick, offer the most severe summer heat problem. It was
this problem which led to the development of air-conditioning
for summer cooling.
One of the most acute heat problems faced by man is to be
101
found inside the tanks engaged in desert warfare. When closed
for action, they quickly become veritable ovens in which the
occupants suffer 4 terrible torment. The steel turret readily
absorbs the sun’s heat and re-radiates it into the interior. Lining
the inside of the turret with aluminum foil should greatly lessen
this heating-up of the interior; it should also give considerable
protection against attack from flame-thrówers or the kerosene
bomb which now makes of the tank a blazing inferno. If tanks
were to be lined with foil and then provided with sufficiënt
mechanical cooling to remove the body heat the occupants
produce, it should be possible for the men to work inside in fair
comfort for hours. At present the heat problem presents a severe
limitation to tank operation in hot weather or tropical climates.
chapter 13
BAD MOODS AND FALLING BAROMETERS
We have seen in PREVious chapters that people
living in regions marked by frequent storms and the accompany-
ing wide changes in atmospheric pressure suffer particularly
from respiratory ailments, high blood pressure, and other upsets.
Acute appendicitis attacks are most likely to come when the
barometer is falling, so much so that knowing surgeons rather
expect an epidemie of cases on such days. This disease is most
severe and fulminates only in the world’s stormy areas; it is
mild and infrequent in the more stable climates of Europe and
most of the tropics.
But the effect of changing weather can show itself in signs far
more subtle than the symptoms of physical disease. People have
long known intuitively that their emotions and personalities
were influenced by their climatic surroundings. In fact, this
awareness is built firmly into the English language with such
phrases as “stormy emotions,” “tempestuous feelings,” and
“a face as dark as a thunder-cloud.” As so frequently is the case,
our closest companions among domesticated beasts provide us
with clear evidence of this phenomenon.
Farm animals are often good barometers of weather change,
exhibiting a growing restlessness and irritability as a storm
approaches. All country children realize this, but those raised
102
in the city have missed the close touch with Nature which comes
from such daily associations. Cattle, horses, hogs, and other
domestic livestock are in their own ways just as natural as wild
animals which roam the untouched forests, and they can teach
us many valuable lessons if we will but take the trouble to stop,
look, and listen.
Time after time these friends on our Indiana farm demon-
strated that sudden weather change is an extremely disturbing
factor in daily life. We had with us for years one particular cow
which acted as an excellent weather gauge. During clear, settled
weather she was a docile and likeable creature, friendly and
co-operative; but on days of falling barometer and approaching
storm, she became most unruly and erratic.
Nell was an easy and voluminous milker of part Jersey heritage,
but too unreliable for me to handle in my very early years.
Almost as soon as I could reach, I began helping with the least
excitable cows at the morning and evening milking. They were
usually milked outdoors in good weather, and it was my duty
to bring them in from the pasture. Many snappy autumn
mornings I would warm my bare toes under some friendly
bossy before rousing her from her pasture bed.
In my later childhood Nell and I were particularly good
friends most of the time. I loved to play jokes on her and she
retaliated now and then with a well-placed kick which sent me
and the milk pail tumbling. There was no meanness about her,
though, for her big soulful eyes assured me all was forgiven as I
clambered up from each such balancing of the score. I soon
learned, however, to treat her with respect, especially on the
off-weather days, when her temper became brittle and her
sense of humour non-existent. On one such lowering June
morning she most unceremoniously boosted* my mother over a
six-foot gate, while we were trying to take away her week-old
calf. Even to-day, at eighty-two, mother becomes irate when
the memory of that undignified handling is revived.
One of my jokes on Nell still doublés me up with laughter
whenever I recall it. It occurred on one of thosc restless evenings
before a storm, when flies and mosquitoes had made milking
difficult and kept everyone on the move. Just at dusk I carried
out a basketful of com nubbins for the cows, since scarcity of
rain had made the pastures short. Corn to them was like candy
to hungry children, so they quickly gathered around for the
treat. To the first nubbin thrown out I had attached a long piece
of thread, and just as NelPs nose touched the corn I gently
pulled it away. She followed it a step or two, then her ears went
103
forward in wonder. Puzzled by this mysterious behaviour of the
nubbin, she regarded it closely a few seconds, then cautiously
reached for it again. This time, as it moved away just beyond
reach of her hungry tongue, she emitted a low, rumbling groan.
A wild look came into her wondering eyes. One more twitch of
the corn and around the corner of the barn she fled with a terrified
bellow, tail pointing high. She might have been as puzzled, but
probably would not have been as emotional, if the trick had
been played on a rising-pressure day.
Horses, especially the more excitable ones, are also very likely
to behave in unexpected ways when the barometer is falling.
They become more irritable, fighting each other and frequently
disobeying orders. On stormy days they are most inclined to
bolt at the slightest opportunity and provide the disastrous
runaways which farm children remember so vividly throughout
their lives. Hogs, too, fight more among themselves on these
days—in fact, I suspect that an hourly count of their fights
through the week would provide a good measure of barometric
changes.
Man’s closest companion, the dog, becomes restless and goes
off on his longer scouting trips when a storm is approaching.
In one large American city with a leash-law all loose dogs are
picked up and taken to the pound. The pound-keeper insists
that dogs smell approaching storms and run out to take their
exercise while they can. His pick-ups are much more
numerous on days before bad weather begins. It is only the
restlessness common to all species, however, which drives the
dogs into unwonted activity when the barometer is falling. Like
the farm cattle and horses, dogs also are more perverse then and
likely to snap at a friendly hand. For safety’s saké, confine your
petting of strange canines to rising-pressure days.
Fishermen given to the telling of tall ‘tales become highly
excited about the way fish rise for bait at certain weather phases.
Anglers* journals have discussed the matter at great length,
finally concluding that barometric pressure change is probably
responsible. A dozen fishermen scattered over a lake may have
been casting for hours or days without luck and then have the
fish suddenly strike at every cast made. As a boy I recall that
fishing in our gravel pit was best the day before bad weather set
in, when the barometer had just begun to fall. Several of my
scientific friends who are rabid anglers take the matter quite
seriously.
People are no more immune to the psychological effect s of
weather change than lower creatures, although the notorious
104
pride of Hom sapiens usually prevents him from admitting it.
We all like to blame our occasional “blues” on concrete, reassur-
ing things, such as worries about the future, and during domestic
squabbles each person is dead sure the other person is at fault.
A wiser course might be to take a look at the barometer, for
human beings respond just like other animals to falling atmos-
pheric pressures and approaching storms. Family mombers are
more irritable on lowering days, when husband and wife snap at
each other and the children seem perversity incarnate. All of
us remember the low-barometer evenings when we arrived home
exhausted from a day in which everything went wrong only to
find the whole family on edge and intolerant of every suggestion.
Each person is inclined to overlook his own irritable state and
blame any unpleasantness upon unreasonable attitudes of others.
Those are the evenings children are chastised because a parent
is tired and irritated, although it is true the children themselves
are more likely to be unduly perverse.
A heavy rain clears the air at such times in more ways than
one, for then the barometer usually begins to rise and good
nature again prevails in the home. Even in their sleep many
people are restless before a storm, tossing with vivid and night-
marish dreams. Our whole family sometimes awakens when a
low-pressure crisis comes along in the middle of the night, and
inquiry of other people next day frcquently reveals many
instances of similar behaviour. So, do not always blame a child’s
wakefulness or his refusal to eat what you thought good lor him
upon mere perversity—it may be only the weather!
Perhaps the children of tropical natives are well behaved
because they are not subject to the frequent weather changes
which disturb temperate-zone residents. Human relationships
everywhere would be more peaceful and unruffled if people
would only realize the effect of weather on their dispositions and
make proper allowance for little flare-ups. Try it out on your
own family; you will soon have them laughing off situations
which previously led to disagreeable bitterness. When my wife
and I look at our children asleep after these quarrelsome even-
ings, we often wonder how we could have been so severe. But
our resolve always to keep good-natured with them usually lasts
only until the next period of low pressure.
People subject to severe headaches or fainting spells most often
have their -attacks when the barometer is falling. Attempts at
suicide are then much more likely to occur. Low spirits and an
inability to think clearly lead to a feeling of frustration and
hopelessness in many people. At such times life seems scarcely
105
worth while; but as the storm passes on, everything assumes a
more cheerful aspect.
A few years ago in Tokyo statistics showed that people were
more forgetful on low-pressure days. When the barometer was
falling, bus and street-car passengers left more packages and
umbrellas on the vehicles and put an extra burden on the lost-
and-found department. Traffic accidents in American cities are
also most numerous in such weather, but in many cases the
drivers may be hurrying to reach their destinations before the
storm breaks. Industrial accidents, however, show this same
increased frequency on days of falling pressure. Even childbirths
seem precipitated in veritable epidemics at such times, according
to some of my obstetrical friends.
Some people, hypersensitive to weather change, respond to
every cloud which hides the sun. Sunshine and shadow keep their
emotions jumping from elation to depression, and on days of
steadily falling pressure they become morose and dejected. The
exact mechanism by which such weather changes affect human
beings in so many ways is not yet known. One of my fellow
investigators in this field, Dr. Petersen of Ghicago, believes it’s
all due to shifting Chemical balances in the blood and body
tissues, and he may be right. Other preliminary findings indicate
that our tissues take up more water at such times and a resulting
slight swelling of the brain may upset us emotionaily. Since the
evidence is not yet entirely convincing, we can only say that so
far we do not know.
When we are equipped for close study of pressure change
effects under controlled laboratory conditions, we will probably
find just why these things happen to us—and perhaps how they
may be avoided. They result only from several hours of falling
pressure acting on our tissues, for quick ascent in an elevator or
airplane is apparently harmless. Investigations of pressure effects
are being greatly stimulated by the marked increase in air
travel—both civilian and military—and no doubt researchers
will soon be able to report interesting results.
Even though the reason for such effects is a mystery still,
proper appreciation of their presence will take much of the stress
and unpleasantness out of life in stormy regions. In my own
family, greater tolerance is exercised on those days when we
know we can expect each other to be more restless and irritable.
I have learned in my own work that some days are good only for
routine jobs, while on others difficult tasks are readily accom-
plished. A falling barometer is particularly bad for the type of
cerebration required in writing, so much so indeed that para*
106
graphs written under such conditions usually need complete
revision. For highest quality output give me an early moming
of rising pressure and a cup of fragrant coffee! Lines written then
are scarcely recognizable as my own after the caffeine effect has
worked off and the pressure has started to fall.
If you are in business, avoid your most difficult customer on
falling-pressure days. His instinctive reaction is most likely to
be curt and unfavourable; he will look upon you with a suspicious
eye. Gall on him when fair weather and a rising barometer are
standing by as your allies. If you must give a lecture or make
some other sort of public appearance, pray that the weather may
be clear and cool. At such times, even the feeblest attempt at
wit will be appreciated and your delivery will be at its peak.
Attack your most difficult problems on the mornings of rising-
pressure days, when to the favourable weather there is added
the barometer’s daily climb from its post-midnight low.
Some day, when we know more definitely just what falling
pressure does to our body efficiency, perhaps we will have
school buildings equipped for pressure control. Then we may
elimlnate those days when both teachers and pupils are ineffi-
ciënt, when everyone is restless, irritable, and susceptible to
wandering attention and blurred intellect. The control of indoor
pressure will probably be one of the future’s major developments
in indoor conditioning, and its first application should certainly
be to school buildings. We shall have more to say in a future
chapter about man’s effort to create made-to-order weather.
chapter 14
GLIMATE AND HUMAN REPRODUCTION
1 hose who have spent their lives studying the
dim corners of the subconscious mind teil us that stronger even
than man’s tremendous drive for self-preservation is the deep-
rooted urge to preserve his species on the face of the earth. The
destructive forces of the most violent wars, including the present
conflict, are puny when compared with the long-term interplay
of great forces which make for larger populations. By the year
2000 the world will probably house a half-billion more persons
than it does to-day—wars or no wars. Despite the fact that
reproduction is one of the most vital of all human functions,
however, many of the factors influencing it are still a great
mystery to modern Science.
What are the reasons for vast population trends? Why is
fertility declining in England, France, and the United States
and rising in Japan and Russia? Although complete answers to
these and other questions are impossible, scientists have studied
certain factors affecting the general picture. Diet plays some part,
but the exact effect is not at all clear. Animal-breeders are
aware that proper food and vitamin supplies are highly important
for the best reproductivity. But in human beings we see highest
birth rates among the most poorly nourished third of the popula-
tion. For some unknown reason, women run down with advanced
tuberculosis or other weakening disease are often quite
fertile.
The economie factor is undoubtedly important. Perhaps you,
like many other moderns, feel that reproductive fertility is more
of a curse than a boon. Children are no longer economie assets,
it is true, since unlimited and cheap mechanical power has taken
over so much of the world’s work. Expensive staudards of living
make child-rearing and proper education a considerable econo-
mie burden, particularly if the children attend college. Hence
is it that married couples are coming more and more to consider
children a luxury which automatically deprives them of many
other pleasures in life. Most modern women look forward to a
first child as one of life’s greatest experiences, a few welcome the
second, but beyond that it is only the unusual mother who does
more than tolerate further progeny as an unwelcome result of
marital relationship.
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There is nothing, however, which enriches adult life as much
as the rearing of a family. Overpopulated though the earth may
be, with more power already available than man knows how to
use, children still are among the most essential ingredients of a
well-rounded existence. Of course we want them to be blessed
with lusty health and vigour so that repeated illness will not
burden us with worry and economie drain. Ability to reproduce
well is therefore still an important part of life, and we should be
interested in the factors which favour or hinder it. Here is where
climate and the seasons enter the picture, for temperature of the
environment and rate of food burning allovyed in your tissues
dominate your reproductive powers. The following pages of this
chapter will show not only that your own fertility is highest
during certain seasons, but that you can take advantage of this
108
important fact. If yöu select the proper time of year to conceive
a child, its chances of success in life and good health will be
tremen'dously increased.
Your fertility is highest when outdoor temperatures range
around 65° F.; conceptions then occur most readily and the
offspring are most' lusty. Winter temperatures averaging below
40° F. make you somewhat less fertile, even though you may be
more active physically; and as mean summer temperatures
climb above 70° F. you decline in both fertility and bodily
vigour. You probably had no idea you were so affected by
changes in temperature and would like to have proof that it is
so. You cannot very well test it out on yourself without en-
countering troublesome social difficulties, so look instead at the
fluctuations in fertility other people show as mean temperatures
go up and down through the seasons.
Live-birth statistics paint a vivid picture, if the births be dated
back nine months to the time of conception. Birth in itself is of
little importance, even though we do celebrate it every year as
long as we live; it is only a more or less inevitable outcome of
earlier events. Of much greater importance are conditions
prevailing at the time of conception, when the characteristics
and vitality of the parents’ germ cclls unite to mould the off-
spring’s future. Throughout pregnancy the mother only nourishes
and shelters the new life as it starts unfolding.
Starting at Montreal, where summer warmth, is ncver de-
pressive, fertility hits its peak in midsummer and sinks lowest
during the steady cold of winter. In Boston there is slight re-
duction during July and August when mean temperatures rise
slightly above the 70° F. line, but in Cincinnati this summer
drop becomes more definite. In the steady moist heat of Charles-
ton^ summer the fall in reproductivity becomes marked, but it
is followed by good recovery through the autumn coolness.
Even more striking reduction is found at Tampa, conceptions
being fully a third less during summer heat than during the
mild winter coolness.
Japan and other countries blanketed by the extremely de-
pressing heat of the Oriental monsoon summer show the most
extreme fertility changes. Japanese conceptions reach their peak
during the cherry-blossom season, when most neariy ideal
weather conditions prevail (April to June). With the onset of
monsoon heat in late June, reproductivity takes a nose-dive and
remains at a low level until October coolness initiates a slow
revival. Marriages in Japan also reach a high peak at the cherry-
blossom season, but éven if every wedding were followed by
109
immediate conception, not over a tenth of the season’s rise in
conceptions could be thus accounted for.
The beauty of the blossoms themselves helps to make that
season the most emotional one in Japan, so temperature may not
be the only factor responsible for the high conception rate.
Until the present war with Japan broke out, much had come to
be made of cherry-blossom time in Washington also. Perhaps it
is significant that even before war began steam shovels were
uprooting many of the trees lining the drives in Potomac Park.
A few years ago, several thousand of the trees were planted in
one of Cincinnati’s parks which has since become quite popular
for outdoor evening dancing. I shall watch with interest for their
effect upon the city’s birth rate!
A few years ago one of my colleagues spent some time as
visiting professor at one of the large Japanese universities. He
became interested in houses of prostitution (a purely platonic
interest, of course!). Such places in Japan are closely supervised
by the authorities, and the compilation of complete and detailed
statistics shows that Germany has no monopoly on Teutonic
thoroughness. Every day the keeper of each house officially
informs the police exactly how many patrons were received.
These figures, obtained by the professor, show no significant
reduction in the use of brothels during the monsoon summer heat.
A Japanese friend tells me that sex relations are fully as active
in summer as at other times of the year. The summer decline
in conceptions must therefore represent a true reduction in
ability to reproduce.
It has been suggested that the reduced summer conception
rate of America’s middle and lower temperate latitudes may be
due to longer hours of outdoor work during that season, with a
higher rate resulting from winter idleness. The same reasoning
fails to hold farther north, however, where highest conception
rates coincide with summer activity and lowest rates with the
long winter nights. The condition is one of real alteration in
biologie fertility and can readily be brought about in laboratory
animals by changing only their ease of heat loss.
Our hundreds of white mice kept at 65° F. became so fertile
that practically every mating resulted in prompt conception.
The litters were large in number and of high vitality, with very
few stillbirths or infant deaths. Within two weeks after the
temperature of the mouse quarters was raised to 90° F., how-
ever, conceptions were difficult to achieve and litters were small
and puny. Many animals were bom dead and many more died
before weaning age. These differences occurred even though
110
mating was carried on just as freely at 90° F. as at 65° F. The
reproductive organs, studied under the microscope, showed
reduced activity in the heat. Complete sterility can be induced
by raising the temperature three or four degrees higher
still.
The use of artificial fever machines has demonstrated that
human reproductive organs also lose their potency for several
weeks after as little as a single five- or six-hour fever treatment.
Production of spermatozoa is exceedingly low for the succeeding
month. There have also been instances of valuable race-horses
rendered permanently sterile by a single day of excessive heat.
A Kentucky blue-grass colt became overheated one sizzling day
while his car was standing in the railroad yards of a certain city
awaiting an outgoing train. He apparently recovered, but had
lost his racing edge. Sold for stud purposes, he was later found
to be completely sterile.
Breeders of small animals around Cincinnati frequently find
that their charges are almost completely sterile by the end of a
hot summer, while the same rabbits, mice, or guinea pigs kept
in cooled quarters continue to reproduce profusely. One beautiful
male rabbit, known to be highly fertile, was overheated in our'
laboratory hot room, but recovered to apparent good health.
Afterwards, repeated matings showed him to be permanently
sterile.
In Panama warmth the prolific guinea-pig becomes a poor
breeder, improving slightly during the short dry season, when
low humidity renders the warmth less depressive. Large numbers
of guinea-pigs are required for certain hospital and laboratory
procedures in Panama, but those imported from the north
endure the heat poorly and are of little value. Last year we
equipped a room for 70° F. temperature and found that pigs
placed in its coolness almost at once regained their famous
productivity.
During the severe heat of the 1934 summer in the Middle
West, human fertility was sharply reduced. Kansas City showed
a 30 per cent. reduction in conception rate during the month
when midday temperatures regularly rosé above ioo° F. (The
usual summer decline is only 15 per cent.) All through the
Middle West birth statistics showed the same sharp decfine for
conceptions during that period of blazing heat. .
Thus, prevailing temperatures profoundly affect reproductivity
which—depending on the weather—may vary all the way from
100 per cent. fertility to complete sterility. But the problem is
not merely one of your own capacities; temperatures not only
affect the number of progeny, but also their vitality and ability
to survive. Human stillbirths and infant deaths are most numerous
at high temperatures, just as we found with our laboratory
animals. Since you may be more interested in the quality than
in the quantity of your children, you must remember that the
healthiest offspring are conceived during the season when your
own fertility is greatest.
My parents were practical people, with little faith in the
sayings of crystal-gazers or fortune-tellers. They sought no
horoscopic reading of their children’s destinies. To them one
month of birth was as good as another, even though they recog-
nized season as an important factor in animal breeding. Their
six children were bom in six different months—January, April,
May, August, September, and December.
In those days there was no evidence that the season of con-
ception exerted a marked influence over the child’s entire future.
If my parents had even suspected that winter or early spring
conception would confer distinct advantages on their offspring,
I am sure they would have made every effort to give us such
benefit. At that time, however, it had not been shown that the
‘volumes of IVho’s Who are largely filled with the names of people
conceived during the winter or spring months, that people
conceived then tend to live several years longer, and that the
likelihood of their entering college is almost twice as great as it
is among those conceived in midsummer heat.
This knowledge was not even available during the years when
my wife and I were raising our own children. However, my older
son and his newly-wedded wife have already been told of its
implications and importance for the future of the children they
intend to rear. My daughter and younger son also became
keenly interested in the subject as they read the preliminary
manuscript for this chapter. Most people \yish to give their
children all possible care and advantage in life, but few realize
that their efforts should begin even before their children have
been conceived. Optimal health and vigour in the parents are
just as important as season of conception for the child’s future,
but few couples consider this important fact. The facts here
presented, however, will be of great interest to those forward-
looking few who desire to give their children every possible
advantage. ,
Investigators in various countries have studied the influence
exerted by season of birth, but Ellsworth Huntington, research
geographer of Yale University, has gone into the subject most
deeply. His book, Season of Birth, lts Relation to Human Abüities,
112
is not recommended as light reading, but it does contain a wealth
of interesting information.
Every mother may not expect her son to become President,
or sit among the nation’s mighty, but she hopes to see him rise
somewhat above the common level. She and her husband can,
if they will, greatly increase the son*s chances for success in life.
The child’s hereditary background btfcomes definitely fixed
when his parents wed, but the activation of his inherited abilities
is largely determined by the physical environment under which
he is conceived and lives.
Prospective parents of middle temperate latitudes should keep
in mind that their own bodily vigour goes through a yearly
cycle, rising to a peak in the spring, declining sharply through
summer heat, and then recovering again during the autumn
and winter. Among the thousands of prominent peoplc in
Who's Who, conceptions rosé steadily through winter cold to a
high spring peak and then declined sharply to the year’s low
point in midsummer.
Your child stands the best chance of being a success if he is
conceived during the season when conceptions are most numerous
in your locality. To be sure, criminals and certain types of the
insane are also more frequently conceived during the same
optimal season, but the dividing line between genius and in-
sanity has always been a narrow one. Proper selection of a mate
should reduce the chances of insanity developing in your children,
while the right kind of home environment will go far toward
suppressing criminal tendencies. If you prefer the greater safety
of mediocrity for your children, then you should choose the less
vital seasons for their conception.
Washington and Lincoln were both born in February. Their
greatness was probably due to the fact that they were conceived
in May at the year’s peak of vitality, for American prc-eminence
has always been closely associated with spring conceptions.
Twenty-seven of our thirty-one presidents were conceived during
the eight months from December to July, and only four during
the remaining third of the year. Not a single President was
conceived in August heat, or born during May or June. Elevcn
of the 31 were conceived the first quarter of the year, 10 in the
second, 4 in the third, and 6 in the fourth. Let those figures be
your guide in choosing the season of conception for your children
—not in the hope that each of them will become world-famous
if properly conceived, but simply so that they may be given this
potent advantage in later life.
As a start toward future greatness, you probably hope your
”3
child will be able to obtain a college education. If you have
ample means, this may worry you little; but those means may
be dissipated in the world turmoil now going on before your
child is ready for college. It would be safer to have him conceived
during the season which starts him off with sufficiënt energy to
carry him to college on his own initiative. In the northem United
States a youngster conceived in March is half again more likely
to enter college than one conceived in August. Far greater *
parental vigour seems transmitted to offspring conceived from
December to March—vigour which drives the new individual
ahead to develop faster, live longer, and accomplish more.
Even puberty shows a significantly earlier onset in those conceived
during winter cold.
Season of conception affects the vitality of the offspring much
less as one goes south from middle temperate latitudes into
subtropical warmth. The cool season still is best, but its benefits
are less striking. In real tropical heat there is no optimal period—
vitality is low at all times of the year. Prospective parents living
in the tropics who desire to practice the highest type of eugenics
and give their children all possible benefits should spend several
months in northern cold before conception takes place. One
young couple in Panama, hearing these facts, congratulated
their infant on having such a fortunate background, for they
had spent several months in Canada just before conception
occurred.
Probably much of my own restlessness and driving curiosity
has resulted from a fortunate March conception—at the very
peak of vitality for the latitude of my birthplace. One of my
children is also fortunate, with the background of a February
conception, but the other two were conceived in October. If I
had only known earlier of this ingrediënt in the recipe for
advantage in life!
These remarks presuppose active timing of conceptions by
prospective parents. Such control is widely practised, however,
and promises to become even more so as new marriage laws
compel young people to undergo medical examination before a
licence can be issued. These laws bring people more in touch
with physicians, many of whom are quite willing to assist in-
telligent couples in properly spacing their conceptions.
As we emphasized earlier in this chapter, widespread use of
inanimate power on farms and in industry has tended to displace
man-power and has made a child more of an economie liability
than an asset. This change is probably responsible for the
sharply declining birth rate and the increasing number of
114
childless marriages. There were ten children in my mother’s
family, seven in my father’s, and six of us at home during my
childhood. But the six of us have a total of only eight offspring.
Average family size has declined from six to less than three
children within one generation. Since quality must now take
the place of quantity in human reproduction, parents should
carefully consider the seasonal and climatic factors which alter
the quality of their progeny.
Keen intellects and high vitality will be at a premium in the
troubled decades of future world reconstruction. Children
conceived during the most favourable seasons have an exception-
ally good chance of possessing these qualities—all that is required
is proper parental foresight. See to it that your offspring never
look back as adults and blame you for lack of such thoughtfulness!
CHAPTER 15
MADE-TO-ORDER INDOOR CLIMATES
We can do nothino about curbing or modifying
the vast outdoor climatic and weather forces which have so
much influènce on our vital rhythms and health. But in Chapter
11 we have already shown that a socially minded community
can and should do a great deal to control the man-made climates
which result in the great clouds of dust and other potentially
dangerous combustion by-products over our industrial centres.
Another method of handling the problems of our surroundings
is to escape from them into that form of localized artificial
climate known as air conditioning.
The benefits of such artificial environments may be illustrated
by an interesting case in Manila. In a local factory 100 Filipino
women were busy wrapping and packaging sticks of bubble gum.
The manager had installed cooling equipment to maintain a
65° F. temperature so that the gum would be kept hard while
being handled. This he had done with many misgivings, since
Filipinos were extremely sensitive to chilling. The labour supply
there was plentiful, however, so he had gone ahead. Bundling
the women up in sweaters, shawls, woollen dresses, and stockings,
he had advised them to eat lunch in the workrooms and to leave
the wrapping room only at the end of the day. They thus had
avoided the shock of frequent change from indoor cold to outside
"5
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does not require a warming of the air in winter oir the cooling
of it in summer. I refer to reflective radiant conditioning, as
demonstrated a few years ago in my laboratory, in which all
warming or cooling of the room occupants is done entirely
through radiant channels.
Heat or infra red rays travel through the air at the speed of
light or radio waves (186,000 miles a second) without any
appreciable warming influence. Their warming effect occurs
only when they strike some solid body which can absorb the
beams. The absorbed rays cause the atoms of the object to move
violently, and the resulting kinetic energy of motion produces
heat. A person’s heat loss can readily be controlled through
radiant channels alone, no matter how hot or cold the surround-
ing air may be, if arrangements are made to govern the amount
of this radiant heat falling upon or leaving his skin surfaces.
Everyone knows the sharp contrast in comfort between standing
in deep shade and out in the hot summer sun, even though
actual air temperatures may be the same in both cases. And in
cold winter air, it matters greatly whether you are on the sunny
side of a building or in its shadow. Those enjoying winter sports
on the mountain slopes of Switzerland or Idaho are kept warm
by the sun’s radiating heat waves reaching them through zero
air. European air-conditioning engineers made some use of this
principle by imbedding hot water pipes in the ceilings or floors
so that the warmed surfaces might radiate heat to the occupants.
Remember that this is radiant heat, the kind which does not
raise the temperature of the air between its source and the
absorbing object. They thus succeeded in achieving comfort at
air temperatures ten degrees cooler than those required by
American air-conditioning methods.
Scientists at one large industrial concern in America tried for
several years to perfect a method for winter heating and summer
cooling through control of wall temperatures. Using metal wall
surfaces, they could make lightly clad persons quite comfortable
in zero air by having the walls radiate heat. Many persons
understand this sort of situation in which heat rays pass through
air, strike the body, and warm it as a result, but they find it
difïicult to grasp how heat may be removed from the body by
radiation. The main point is that the body, like any other object,
can lose heat by emitting infra red rays, and, if the walls of a
room are cooled instead of heated, these rays are removed from
the room confines as fast as they are given off from the skin.
The researchers proved this by placing persons in the room
at no° F. Then they lowered the wall temperature. Despite
118
the sizzüng heat, the subjects relaxed comfortably because their
bodies were able to eliminate the excess heat by radiation. These
tests were interesting and valuable. Judging by their skin sensa-
tions, occupants of the experimental room often could not
guess whether they were in cold air or warm. For some reason,
the hot air was not even disagreeable to breathe when body
skin surfaces were losing heat readily to the cold walls. In quite
thorough fashion, the scientists demonstrated that bodily
comfort could be obtained by control of wall temperatures
regardless of prevailing air conditions.
The studies were finally abandoned for two reasons. There
was no way of controlling wall temperatures within reasonable
economie limits, either for construction costs or for maintenance;
and walls chilled for hot summer weather were always wet with
water which condensed upon their cooled surfaces. Obviously,
no heating system will sell if its hot-weather operation causes
wall surfaces to drip with moisture.
In my laboratories the radiant idea was carried a step further.
Instead of using hot or cold wall surfaces, I covered all the
inside walls of an experimental chamber with aluminum foil.
It is a highly efficiënt, mirror-like reflector of all heat rays, so
much so that its surface temperature rises very little even when
intense heat is directed at it from a close-up source. On two side
walls of the foil-lined room, I installed steel plates which could
be chilled by fluid circulated from an outside compressor unit.
The air in this room was kept hot and moist at all times (930 F.
and 70 per cent. saturated) by means of an automatic con-
ditioning unit. In another foil-lined room, arrangements were
made to chili the air down to freezing temperatures, with
ordinary electric radiant heaters as a source of heat rays.
I found that a person could be quite comfortable in the tropical
moist heat of the hot room when he lost body heat solely by
radiation to the cold plates—either directly or by reflection
from the foil wall surfaces. With all the cold plates in operation,
loss of body heat was so rapid that actual chilling resulted if a
person sat quietly reading for an hour. Rats and mice grew just
as rapidly, and with as high vitality, as in the 65° F. air of my
ordinary cold room. An assistant, in caring for the animals,
found that she needed a sweater to keep from being chilled—and
this in air at 93° F.!
Metal cages, wooden objects, and clothing in this hot room
were cooled by radiation of their heat to the cold plates, while
all foil surfaces remained at the 930 air temperature. A person’s
clothing thus became several degrees cooler than the air im-
119
mediately in contact with it. This is a resnlt difficult to ïmagine,
but it actually occurred. As one entered from severe outside
summer heat, no immediate difference was noticed; but within
a few minutes a feeling of cool comfort developed as clothing
temperatures dropped and more rapid loss of body heat became
possible. No shock whatever was experienced on passing from
the room’s comfort into outside heat, for air conditions were
approximately the same inside and out. Here was adequate
summer comfort without air cooling and the shock and hazards
it brings to those entering or leaving the conditioned confines.
In the other foil-lined room, radiant heat furnished delightful
shirt-sleeve comfort while air temperatures remained near
freezing. A pleasing phase of this set-up was that one had cold
air to breathe while the remainder of the body was properly
warm. By sufficiently increasing the input of radiant heat (still
keeping air temperatures low) a person would find himself
perspiring freely while surrounded by cool air. Under such
excessive radiant heat load, animals showed the same slow
growth and lowered vitality as in ordinary tropical moist
heat.
Reflective radiant conditioning, effectively demonstrated in my
experimental chambers, offers alluring advantages for both
winter and summer use. In the first place it removes the necessity
of setting up sharp differences between air conditions indoors
and out; this was the particular point I had hoped to achieve
because of its health implications. Another very definite advan-
tage is the marked reduction in power load needed either for
winter heating or for summer cooling. Different engineers and
architects have estimated that the fuel or power load would be
reduced 60-80 per cent., since little is wasted in warming or
cooling the air mass or wall materiais. Such reduction would
bring conditions easily within the gas or electric field, thus doing
away entirely with the home use of coal and all the resulting
smoke nuisances.
Another benefit of reflective radiant conditioning would be
its saving in insulation costs. Since the reflective foil surfaces
remain cold in winter air and hot in summer—at practically the
same temperatures as those of the outside air—heat transfer
through the wall would be small. In addition, the foil surface
radiates on into the room very little of the heat which comes to
it through the wall. Thus, the surface is highly reflective for rays
striking its surface, but has almost no power to emit heat which
may actually be in the foil itself. In this conditioning system the
walls need be constructed to turn wind and rain, but with little
120
consideration for heat-transfer values. This is sharply different
from the expensive insulation needed for efficiënt air conditioning.
One installation of reflective radiant conditioning has been
made under actual field conditions. This was in an operating
room of a large hospital where surgeons and nurses enjoyed
delightful comfort even while midsummer air temperatures in
the room remained above 90° F. Certain further developments
are needed, however, before this type of indoor conditioning
can come into wide üse. Means of decorating the foil surfaces
must be found, for few people will be willing to have shiny walls
in their homes; but such decoration must not interfere with the
foil’s mirror-like reflectivity. Scientists must develop paints
which are heat-transparent in thin coatings. Certain lacquers
can be used safely on the foil surface, but pigments must be found
to put colour into a room. Finally, the system calls for a'heat-
transparent plastic to protect the heating and cooling plates
from room air, since in radiant conditioning it is desired to leave
air tempertaures as little changed as possible. One material
already in use has been found to be about 50 per cent. trans-
parent to heat rays (that is, it allows about half the heat rays
striking it to pass through), and careful search in plastic labora-
tories will probably yield another of the desired efficiency. With
such sealing-in of the plates, the only heat entering or leaving
the room will be that in a radiant form.
A housing research unit in the engineering college of another
university is at present equipping a small cottage for radiant
conditioning along the lines followed in my experimental
chambers, with a conventional air-conditioning system in an
adjoining companion cottage. There comparative operating
costs and working efficiency will be studied under actual
field conditions, and the method made ready for practical
application.
It has been quite definitely shown that skin sensations of heat
or cold depend upon the rate of heat gain or loss and not on the
manner in which the heat arrivés or départs. Air, clothing,
or other materials feel hot or cold according to the rate at which
they conduct heat to or from the skin by direct contact. But
radiant heat from a distant source—such as the sun—also feels
warm because it too adds to the skin’s heat. These principles
explain why one can feel cool at 930 F. In my foil-lined hot
room, with the air kept at 930 F., a distinct sensation of cold can
be obtained by holding the palm of the hand out in front of the
cold plate. Even though the hand be entirely surrounded by
hot, moist air, the radiant heat loss from the skin to the cool
121
plate causes a definitely chilly feeling on the palm. It seems to
matter little to the body through what avenue its heat is lost,
just so the total rate of loss be adequate.
Of course, air conditioning is not concerned solely with
heating or cooling of the air, but heat control does constitute its
major concern. Humidity changes and air motion are only
secondary factors to facilitate the warming or cooling effect
upon the body. Cleansing or filtration of the air, however, is
another separate and important part of air conditioning, one
which is greatly needed in the dirty atmosphere of our industrial
cities. Other air-conditioning gadgets of limited application are
the ozonizers and sterilizing lights now being installed in many
places. Sterilizing curtains of ultra-violet light have been found
especially useful in hospitals to prevent the carrying of disease
germs from one patiënt to another by air currents.
Still another proper function of air conditioning is the supply-
ing of fresh air to the room. No one yet knows just what the
difference is between fresh and stale air ëxcept that one is
pleasant to breathe and the other is disagreeable. Gertainly
staleness is not an oxygen lack, nor need it be concerned with an
accumulation of body odours.
Staleness of air has been thought by some to be related to the
degree of oxygen ionization. Ordinary outdoor oxygen exists
in several different forms—as 02, 03, and 04. Its reactivity
increases sharply the greater the number of atoms there are
associated together. Ozone is presumed to be 04 and is the most
active form of oxygen known. “Stale” air at once becomes
“fresh” when passed through a proper ionizing chamber to
reactivate its oxygen. Temperature plays an important part in
this ionization, for the active forms go back into the inactive
more readily when the temperature is high. One of the quickest
ways to make room air lifeless and undesirable for breathing is
to pass it over hot metal surfaces, as is done in many warm-air
heating plants. Room air thus tends to retain its freshness much
better if it is kept cool. Radiant conditioning offers a distinct
advantage here, for indoor winter air can be kept cold and fresh
much more readily when the room occupants are being warmed
by radiant heat. In fact, Windows could be kept open in mid-
winter provided no noticeable draughts were present.
Filtration or proper cleansing of outside air as it is taken into
a room prevents dirt accumulation both in human air passages
and on room furnishings. Such cleansing is badly needed in
industrial or densely built-up urban regions. Many people
carefully filter all the air taken in during the day but throw their
122
bedroom Windows wide open at night, when the outdoor air
is foulest. The housewife can see her window curtains disin-
tegrate where the night air strikes them, yet she seldom considers
that the foul air may exert a similar corrosive action on the tissues
of her respiratory tract. During winter nights, when the “smog”
hangs thick over a city, one’s nasal linings become heavily
coated with the black soot and ash mixture coming from the
neighbourhood chimneys—unless, perchance, the incoming air
is filtered at night as well as through the day. Our handkerchiefs
usually teil the story with their first morning use.
In homes equipped with warm-air heating systems, which
include a fan to circulate the air through the house, the Windows
should be kept shut both night and day during the winter
season; then all incoming air is properly cleansed. Bedroom
temperatures should be lowered during sleeping hours, it is
true, for people usually sleep best when they have cool air to
breathe. But it seems inadvisable to allow all the city’s flue
products free access to your bed-chamber in order to have a
night supply of cool air. Americans have greatly overdone the
fresh-air idea, anyway, particularly with respect to the wide-
open bedroom Windows. Ten degrees of night-time cooling
should be ample, whereas many of us during the winter sleep
in air thirty to fifty degrees colder than we breathe through
the day.
Many people consider summer cooling prohibitive in cost,
but it is no more expensive than winter heating. The difference
lies in the fact that winter heating is essential while summer
cooling is more or less a luxury. Hot-weather comfort is particu-
larly costly in tropical climates, where the cooling load is heavy
and electric rates aie high. Radiant conditioning will be especially
appropriate there, both on the basis of its lower power require-
ment and because it avoids contrasts between indoor and outside
air.
While proper conditioning of man’s indoor habitat may add
greatly to his comfort and health, it is questionable whether it
can go far toward overcoming the more profound effects of given
climates upon whole masses of people. The lucky few will always
enjoy efficiënt conditioning, but only the poorest makeshift
arrangements must suffice for the unfortunate many. Even with
all the wealth and mechanical productivity of America, indoor
conditioning is still rudimentary in the great majority of house-
holds.
In case you plan to join the lucky few, be sure your job is well
engineered for your particular needs. Accustom yourself to
123
temperatures around 7o°-72°F.; if any members of the house-
hold are chilly at -these temperatures,* have them wear warmer
clothing. Overheating is just as harmful for some as chilling is
for others. Bare arms or legs are quite often responsible for
complaints. Women produce less heat than men and usually
chili more easily; so they should be the ones to wear the heavier
clothing indoors. Where both sexes live or work together indoors,
the men should be in shirt sleeves or wearing only a light jacket,
and the women should put on work coats as warm as they need
for comfort. Many offices and homes are kept far too warm
simply because some occupant would rather complain than put
on moré clothing. Granny should have her warm corner and
shawl while the youngsters do their homework off in a cool
study.
Glassrooms at school should be made comfortable for the
children rather than the teacher. Being older and less active,
the teacher usually desires higher room temperatures; however,
her needs should be met by additional clothing rather than by
keeping the room too warm for the children. In school buildings
with central heating and thermostatic control it is probably
wisest to keep temperature regulation out of the teacher’s
hands.
People with chronic rheumatic or sinus infection are always
extra-sensitive to chilling. They chili at temperatures quite
comfortable for normal persons, but this chilling is just as bad
for them as real cold would be. The best solution to their problem
is warmer clothing. Except in hospitals and sick-rooms, tem-
peratures should be adapted to the comfort of the normal well
people rather than to the complaining few.
By making indoor atmospheres more uniform and stable,
air-conditioning engineers have added greatly to our comfort.
Progress toward reflective radiant conditioning in the years
ahead may allow us to hold these gains and add to them other
notable advances. I predict that some day we shall see interior
conditioning done largely by radiant means, with a health
betterment and cost saving which will make us wonder why we
struggled so long trying to do the job through heating or cooling
of room air.
But, as we mentioned at the beginning of this chapter, air
conditioning is merely a drop in the bucket when the small
and isolated spots of man-made comfort are compared with the
vast realms of space where climatic forces work supremely in-
different to man. The first five chapters have shown how these
forces affect people in the tropics; the following chapters em-
Ï24
phasized the driving force and health toll of energizing cooler
climates. In the final part of this book we shall look at the larger
effects of climate and weather on mankind in general. People
who still think of man as a builder of his own destiny will not
like what we see.
125
PART III
CHAPTER l6
-
LIFE, SUNSPOTS, AND THE ATMOSPHERE
Ihe earth is surrounded by an atmospheric cloak
which may seem filmy and intangible, but actually is so large
that it weighs an estimated 5,000,000,000,000,000 (five quad-
rillion) tons. Even in an ordinary room there are roughly 200
pounds of air. It is within this vast expanse of air enveloping the
earth that disturbances take place which cause short-cycle
weather changes and the slower undulations of unseasonable
warmth and cold occurring every few years. It is this airy
sheath which provides the oxygen necessary for life, but within
its environs our very existence hangs by the most slender threads
of cosmic circumstance.
In fact, the earth is lucky to have any atmosphere at all.
Mercury, the smallest of the planets, has none because her
gravitational attraction is too small to hold a vast envelope of
atmospheric particles and prevent them from wandering off
into outer space. Mars, which is about one-quarter the earth’s
size, probably has -just enough water vapour and oxygen to
support simple forms of vegetation, but not mammals like those
found on earth. Although Venus is slightly larger than Mars, its
cloudy atmosphere is mostly carbon dioxide, the gas which
you exhale and which bubbles up in soda-pop and other car-
bonated beverages. Jupiter, Saturn, and the other outer planets
cannot support the life we know because their temperatures are
hundreds of degrees below zero, and their atmospheres are
dense with hydrogen, methane, ammonia, and other unusable
gases.
The earth’s heavy, solid core, combined with adequate size,
gives our planet sufficiënt force of gravity to hold its atmosphere
in place. Even so, only the lower layers of air are dense enough
to support life. A mere 6 or 7 miles away from the earth’s surface
the atmosphere becomes too thin to supply our oxygen needs.
Most people are affected even by riding in an aeroplane at the
usual flight altitude of 2 miles. At 3^ miles the air is about half
126
as dense as at sea level. From there on out for the next 5 miles
it is called “stratosphere” and is inhabitable by man only if he
takes along an additional supply of oxygen to breathe.
We are limited in a downward direction also, for life becomes
difficult in the dense air i-i£ miles below the surface in deep
mines. Serious troubles often arise on ascending from such mines
to surface air conditions. Workers coming up from the deep
South African gold mines take an hour or so for the trip, being
held for several minutes at different levels to allow gradual
reduction in the amount of air dissolved in the blood. Too
sudden an ascent causes bubbles of gas to be liberated in the
blood; these bring on the “bends” by obstructing blood flow
in the smaller vessels and may produce serious damage.
Under-water workers encounter similar limitations and
difficulties since the pressure of their air supply must be doubled
for each 32 feet of depth beneath the water’s surface. For really
deep descents into the ocean, such as William Beebe makes for
his observations of deep-sea life, sealed chambers capable of
withstanding great pressures are used, with surface atmospheric
conditions maintained for the occupants.
Not only is human life confined to a narrow layer of the earth’s
unique atmosphere, but slight alterations in the composition
of the air would mean death to all living organisms. We see the
fish in our rivers die as we pollute the watery surroundings in
which they live, but we seldom stop to consider some of the ways
in which our own atmospheric sea might change disastrously.
The air we breathe is 78*03 per cent. nitrogen and 20*99 Per
cent. oxygen; sudden disappearance of the latter element would
of course result in the death of every land animal in a matter of
minutes. But the atmosphere also contains other Chemicals in
such tiny quantities that it is difficult to realize their extremely
vital importance. There is only about o*03 per cent. of carbon
dioxide in the air, yet elimination of even this small proportion
would start a vicious cycle indeed. Plants, lacking this com-
pound, which is necessary for their existence, would wither
away and die. Herbivorous animals would soon starve to death,
as would man and other meat-eaters. According to animal
experiments by Professor J. Willard Hershey and Charles
Wagoner of McPherson College in Kansas, the rare gas, xenon,
is necessary to life—yet there are only six parts of this element
to 100,000 parts of air!
Even with this fortunate atmosphere, however, life could not
exist without certain other natural coincidences. For example,
during heat waves we look forward to some relief after sundown
» 127
when the day’s heat radiates óff into outer space; but what if
the earth rotated more slowly—or not at all—on its axis? Mercury
and the moon have no such rotation, and their long daytime of
accumulating sun’s heat results in temperatures far too high for
any form of life. During their prolonged nights all this heat is
lost into space, and congealing frigidity prevails. So you can see
the intricate set of fortunate cosmic circumstances lying behind
the existence you so thoughtlessly enjoy day after day.
The terrestrial atmosphere which acts as a vast stage for
weather and seasonal changes is also a protection against radia-
tions from outer space. High-energy cosmic rays and ultra-
violet rays beat down toward the earth but lose much of their
force as they batter against molecules in the great sheathing
layers of air. If these layers were less dense, cosmic rays might
be deadly for man and other forms of life, while ultra-violet
beam§ would burn all things to a crisp. But the atmosphere
allows just enough of these radiations to come through and
benefit man. The ultra-violet beams which pass down to the
earth’s surface promote tissue health and kill germs, while
penetrating cosmic rays produce another desired effect.
As these radiations cleave through the upper air, they are
thought to impart their energy to its molecules and give it the
ionic character which we find so stimulating for breathing
purposes. Only in the cooler latitudes of the earth, however,
does man get a chance to breathe air from these activated outer
'layers. Tropical air is usually spiraling upwards, with no com-
pensating down currents from the upper atmosphere. Incoming
currents there travel along the earth’s surface from temperate
regions as the trade winds. In cooler latitudes, however, the
activated upper air is frequently brought down to us as enormous
masses of cold, heavy air—the “highs”—which sweep across the
continent providing clear cool weather and an atmosphere which
is often like a heady wine to breathe.
The cosmic rays may thus play an important part in our lives
by this effect upon the air we breathe. Perhaps the better supply
of this ionized atmosphere in temperate regions is a factor in the
greater vigour people of such lands enjoy. The rays themselves
also penetrate to the earth’s surface more in middle temperate
latitudes than farther, toward Equator or poles. Our knowledge
of their effects is still very sketchy, however; perhaps some day
their importance will be better understood, just as we are to-day
coming to appreciate the role air temperatures play. Perhaps,
too, a sudden increase in their intensity may some day turn
them into real death-rays for all life on earth.
Another type of radiation striking the earth’s atmosphere is
responsible for the day-to-day and year-to-year changes which
make up world weather and affect human beings in the many
ways described in the previous chapters. Strangely enough,
our weather here on earth is strongly influenced by “weather”
on the greatest body in our planetary system—the sun—for the
sunspots you have been hearing so much about definitely influence
our surroundings and are very like our major storms on earth.
They are whirling in character, originate mainly in the higher
latitudes of the sun’s surface and travel eastward and down
toward the Equator in much the same way our temperate-zone
storms migrate across North America. They may be 100,000
miles in diameter instead of 2,000, but the sun’s diameter is
about 100 times that of the earth. From their centre gases spiral
far outward from the sun’s surface, just as the earth’s surface air
is propelled many miles upward in the centre of our large
cyclonic storms. Heat and electro-magnetic radiations stream
outward from the dark craters. These are the rays which so
seriously disrupt our long-distance telephone, telegraph, and
radio communication. Such disruption is now rather expected
with each new outburst. Those “highs” and “lows” discussed
in the chapter about barometric pressures then come along at
closer intervals, bringing more violent changes and colder
weather to the temperate regions of the earth.
Sunspots large enough to be seen with the naked eye are
present only at or near the crest of the eleven-year cycle, as in
the years 1937 and 1938. They are much less frequently seen
now (1942), and will almost disappear through the next year or
two. They were described in early Chinese writings as well as
by ancient Mediterranean observers. For the last two centuries
fairly accurate records have been kept of their size and number
from day to day. These records show recurring variations from
intense sunspot activity down to almost complete quiescence,
with the time from one crest to the next varying from eight to
sixteen years. An average length of slightly over eleven years
has caused them to be called eleven-year sunspot cycles, although
none of them has actually been of this length.
If you yourself have never seen these spots, you should watch
the rising and setting sun at times when fresh outbursts are
being mentioned in the news dispatches. One clear moming
in mid-October of 1938, while watching a beautiful sunrise, I
was greatly surprised to observe a pair of large dark spots on the
otherwise bright-red disc of the sun’s face. Only after watching
for several minutes to be sure they kept their position on the
Ecmm 129
rising sun was I certain they were not solid objects in our own
atmosphere. On each succceding morning the spots were seen
more to the right on the sun’s face as it rotated on its axis, and
about a week later they had passed around out of sight. The
succeeding issué of Science News Letter carried a photograph of
the pair as its cover design, with a news note about their appear-
ance on an inside page.
Although earth storminess seems dependent to a considerable
degree upon sunspot activity, it has been found that the sun-
spots themselves are in turn dominated by the planets of the
solar system as they revolve around the sun. Curiously enough,
this influence of the planets was first observed for the earth
itself. Mrs. Maunder, the wife of a British astronomer at the
Greenwich Observatory, in 1889 observed that the spots in-
creased and were more numerous on the face of the sun away
from the earth, while on that portion toward us they diminished
in size and number.
Every layman at once wonders how Mrs. Maunder could
know what was happening around on the invisible face of the
sun, but the answer is simple. She did not use a rocket ship for a
trip out into space in order to view the other face of the sun!
The sun rotates on its axis just as the earth does, except that it
takes 28 of our.days for one complete rotation. Mrs. Maunder
simply kept daily count of the spots in each segment of the sun,
and noted that sunspot activity decreased steadily during the
14 days any area was visible trom the earth. Furthermore, she
found more spots on the surface just coming into view on the
left than on that disappearing from view to the right.
Other astronomers have verified Mrs. Maunder’s findings
and have shown that the same effect is exerted by other planets.
Sunspot numbers decline roughly 15 per cent. during the 14
days a given area of the sun is visible from the earth and ap-
proximately 22 per cent. while it is exposed to Venus. Venus is
somewhat smaller than the earth, but it is nearer the sun and
exerts a gravitational force about half again as great as that of
the earth. These tidal effects of the planets upon the sun are far
from simple, however, and astronomers have not yet been able
to unravel them sufficiently to make accurate forecasts of future
activity.
It was Dr. Abbot, of the Smithsonian Institution in Washing-
ton, who pointed out the direct connection of sunspot activity
to earth temperatures. Over a considerable number of years, he
found that Washington temperatures tended strongly to be lower
for the two weeks after each new outburst than for the fortnight
130 ' *
preceding. I myself studied temperature records back through
the last two centuries in Europe and America, and found that
unseasonable cold prevailed in two-thirds of the months during
years of rising or high activity; during years when the sunspots
were declining or low, two-thirds of the months were unseason-
ably warm.
The amount of heat given off by the sun is greater when the
sunspot activity is high, and yet earth temperatures fall in
middle latitudes. This is explained as being due to the more
active convection currents set up in our surface atmosphere at
such times by the more intense sun’s heat, particularly in equa-
torial regions where the heat rays strike most directly. The con-
vection currents are supposed to pass outward toward the poles
at high altitudes and return to the earth’s surface as the polar
cold waves which bring increased storminess and lower tem-
peratures to temperate-zone lands. Whether or not this ex-
planation is correct, it is true that greater sunspot activity does
tend to bring cold and storms to middle temperate regions.
During periods of low sunspot activity the weather is more
likely to be calm and unseasonably warm.
When these periods of exceptional “summer” warmth *and
calm come over the earth, northerners tend to take life at an
easier pace. The result, when brought out by careful statistics,
is a vivid example of how man is under the influence of outside
forces, for with the decreased energy men pursue their business
lives less actively, are less disposed to put forth the effort needed
to support non-essential expenditures, and in every way take life
at an easier pace. Wall Street and other financial centres feel
the passive impact of this rhythm during warm periods of low
sunspot activity and, consequently, such periods are often
accompanied by severe depressions. Heat was present with the
panic of 1857, during the gloomy “seventies,” and with the
breaks of 1893, i9°7j i920j and I929- Our security panic of
1929 occurred a month before the temperatures here began their
prolonged elevation, but severe unseasonable warmth had
already struck Europe four months previously.
Practically every prosperity or boom period, on the other
hand, has been a time of normal or low temperatures. Such was
the stimulating weather preceding the nat ion’s past crashes.
For the last three years of the first World War unseasonable cold
largely prevailed in America, giving a firm basis for the remark-
able expaiision in our wartime industrial output. Temperature
conditions were not quite so propitious for production early in
the present war, for we had been held down by protracted
131
warmth most of the time since late 1929. But there were sub-
normal temperatures generally in 1940 for the first time in over a
decade, and in that year our industrial machine seemed to
shake off its ten-year collection of cobwebs and oil up for in-
tensive action. Moderate warmth in 1941 slowed it down some-
what, but in the first half of 1942 optimal temperatures have
prevailed and allowed our war production to reaph really
amazing levels.
Although the medical profession feels the result of these
weather changes especially strongly, the average physician
seldom realizes how closely temperatures, business activity, and
health are interrelated. When times are hard, he blames his
reduced income on the assumption that fewer potential patients
make calls because they, too, are earning less money and cannot
afford medical service. But the facts invalidate this easy assump-
tion, for general death rates are lowest during those same
depression years when there are fewer calls for a doctor’s help.
The medical profession need not worry, however, for it does not
follow that visits to the family physician actually increase the
risk of death! The high temperatures which accompany low
sunspot activity and influence financial depressions also bring
reduced storminess, greater relaxation—and the human machine
works under lower stress.
During these warm periods respiratory attacks and other
acute infections strike less frequently. Heart failure cases entering
the Gincinnati General Hospital—considering only those
unassociated with bacterial disease—were only a quarter as
numerous through the very warm years from 1929 to 1933 as
they were before or afterwards. Normally such cases are four
times more common in winter than in summer, but during those
balmy winters low summer rates prevailed. Toxic goitre cases
also became more scarce. Quite regularly back through past
depressions in America illnesses and deaths have been reduced
as business activity lessened. Health authorities have always
predicted dire consequences from the smaller expenditures for
health purposes during such hard times, but no such ill effects
ever occur. The health improvement always lasts until the
people again become involypd in another rising tide of business
activity. Hard times severely affect the country’s doctors, for
collections are poor and fewer calls are made upon them.
During prosperity their services are in greater demand to stem
the rising sickness and death rates.
Tuberculosis is one of the diseases showing great improvement
in times of depression, and it is the one which health workers
132
always expect to become worse because of incrcasing poverty
and malnutrition. It benefits greatly, however, from the reduced
storminess and lessened acute respiratory illnesses of the warm
years. The long decline in its death rate is usually accelerated
most during prolonged economie recessions and sometimes
receives a temporary setback with the return of the colder and
more stormy years of better times. Solution of the mysteries of
sunspot and other outside Controls over earth’s weather would
probably go far toward removing the disastrous effects of these
recurring economie cycles which beset us.
I do not mean to infer that weather is the only factor at work.
Wars, mass migrations, changes in population pressure, over-
expansion of production—these are also extremely important
elements in setting the stage and determining the intensity of
the reaction once it starts. It is weather, however, which affects
the energy background in man himself, deciding whether he
shall be energetic and expansive in his planning or whether
fear and inaction shall prevail.
-
All the evidence of this chapter emphasizes the intricate
meshing of environmental factors which makes human life
what it is. It could not exist unless the earth had been able to
hold an atmosphere, unless the earth were tilted on its axis at
just. the right angle. Variations in atmospheric composition,
some of them extremely small, would kill man and all his fellow
creatures, while the air itself is just dense enough to protect
people from the potentially lethal radiations of outer space.
The earth’s great blanket is under continuous bombardment by
these radiations, as well as by the radiations resulting from
sunspots, and their effect plays an important role in the weather
which in turn affects man’s activity and health. Since the sun-
spots themselves seem largely controlled by the positions of the
planets, life—and more particularly human life—is seen to be
part of a vast organic unit, a uilit which includes at least the entire
solar system. Whether celestial bodies outside our own tiny
system also influence our lives has not yet been studied, but
this possibility cannot be excluded.
Without subscribing to the unfounded tenets of astrology,
which hold that the detailed events of every person’s life are
pre-ordained by the positions of planets at his birth, we now
have a scientifically discovered and direct chain of influences
meshing our daily lives into the larger forces of our own solar
universe. The chain cannot be over-emphasized; the planets
in their shifting positions around the sun cause the sunspots to
wax and wane. As a result there arise variations in solar radia-
133
tions to the earth and changes in temperature and storminess.
These weather changes, both short-cycle and over longer periods,
markedly influence our body functioning.
CHAPTER 17
ICE AGES AND GLIMATES OF THE FUTURE
Short-cycle weather changes and the slower
alternations of unseasonable warmth and cold every few years
are rather well explained on the basis of solar-system forces.
Our knowledge is inadequate, however, to explain other changes
extending through the centuries or covering thóusancfs of years.
Most definite of all climatic fluctuations were the slow undula-
tions from one ice age to another. In the most recent of these
the North Polar ice cap spread down over North America as
far as the present courses of the Missouri and Ohio Rivers.
These rivers were raging torrents as they carried away the
melting ice and snow from the ice cap’s fringe. The Ohio River
cut several different channels for itself here at Gincinnati as the
glacier edge alternately advanced and receded through that
era.
Several times these ice ages have returned to the earth,
causing polar cold to prevail far down into what are now tem-
perate regions and compressing the tropics into a much narrower
belt. In the intervening warm periods tropical warmth has
expanded outward toward the poles and the ice caps may have
completely disappeared. It is estimated that only about 30,000
years have elapsed since the last ice age was at its crest. Where
Cincinnati now sits, with its mild winters and hot summers, was
then a grinding, crackling glacier front with a climate similar
to that of Southern Greenland to-day.
Although men were present here on earth long before the last
ice age, their numbers were small and there is little evidence
from which to construct a story of their activities. Since humanity
has actually stepped out of the shadows only within the last
10,000 years, we can devote chief attention to climatic fluctua-
tions within that period. They have been present, but in a much
less drastic form than the changes from ice age to inter-glacial
134
warmth. Evidence left by receding ice caps and glaciers, by silt
deposits along rivers‘fed from melting ice, by salt layers along
inland lakes, by the growth rings of our giant redwoods in the
South-west—all these and information gleaned from recorded
history point to several prolonged cold periods altemating with
centuries of warmth.
Through the last 10,000 years these slow undulations have
occurred with fair regularity, the glaciers and ice caps receding
rapidly for a thousand years or so and then halting or even
advancing somewhat for the next thousand. It was this stair-step
recession which left the long moraines of piled-up gravel and
boulders at intervals over the course of the receding ice cap here
in America. To-day the last ice age is represented only by
isolated mountain glaciers and by the small ice sheets
covering most of Greenland and Antarctica. Another cycle
or two of recurring warmth may well cause their complete
disappearance.
The last millennium of warmth feil within the time of recorded
history, covering the Dark Age period from the fall of Rome to
the Renaissance (from the fifth to the fifteenth centuries a.d.).
During this warmth cereal grains were regularly grown and
ripened in Iceland and wine-making was carried on in parts of
Great Britain where it has not been possible to ripen grapes
through the succeeding centuries. The shores of Iceland were
largely free of ice packs for the finst several hundred years after
its settlement, but since the fourteenth century its northern
shore has again been icebound and its climate has become too
rigorous for erop raising.
The climate of Greenland in the ninth and tenth centuries,
when the Norse settlements flourished there, apparently differed
from the climate of more recent times. Early in the eleventh
century, however, the colonies rapidly declined, with increasing
evidence of rickets in the skeletons of those buried during the
settlements’ decline. The dead were buried deep in the unfrozen
earth during the ninth and tenth centuries, but after that the
graves gradually became shallower as the summer thaws pene-
trated less deeply.
Many of those Norse bodies in Greenland were found almost
perfectly preserved when rising world temperatures had again
thawed out the earth to make their excavation possible a few
years ago. Recent excavations in earth which had been solidly
frozen for almost a thousand years have given us a glimpse of
those settlements as they declined in the oncoming cold. In that
ancient warmth the people carried on extensive cattle-raising—
135
an activity quite impossible in the Greenland of more recent
times.
The scanty records indicate terrible winters of snow and ice
in northem Europe preceding the Dark Age warmth, while the
civilizations of early Greece and Rome were flourishing in regions
which are now too enervating for sustained effort. Egyptian
writings of those centuries teil about winds and storms which can
only 'mean that the cyclonic storms to-day travelling eastward
over Central Europe then passed down the Mediterranean Basin
and on across Asia Minor. Palestine' and the other eastern
Mediterranean countries had a more copious rainfall, better
distributed through the year, than has been the case in modern
times.
The heat of the Dark Ages was at its worst about a.d. 850.
By a.d* 1000 there were evidences in Greenland of returning
cold, and by a.d. 1400 the ice packs had again closed in on
northem Iceland. Through the centuries since the time of the
Renaissance and the revival of learning, cold has largely pre-
vailed. Actual thermometer records go back only two hundred
years, but within that time they show lowest temperatures to
have occurred around 1850, about a thousand years after the
peak of Dark Age heat.
What about the trends of modern times? The records definitely
show that temperatures over the earth have been rising almost
universally for the last eighty years or so, slowly at first but
much more rapidly in recent years and especially during the
last twenty years. Climates have indeed altered since Grand-
father’s day. The winters are milder and the summers hotter.
My father in his later years often mentioned the rigours of his
boyhood winters, contrasting them with the milder tempera-
tures of the twenties and early thirties before his death in 1933.
Even in my own childhood and youth the silky crunch of sub-
zero snow was encountered many times each winter, whereas
now the blankets of snow are wet and sloshy.
Up until very recent years everyone ridiculed the idea of
climatic change. It was claimed that people in later life would
remember more vividly the extremely cold spells, but forget
the milder winters which had failed to leave so strong an im-
print. False impressions of this kind are known to be fostered by
such tricks of memory, so the matter was always treated as
a joke. Ellsworth Huntington and certain other investigators
had great difficulty getting even scientific people to believe their
evidence of past fluctuations. Meteorologists, however, finally
began examining world temperature records of past decades.
136
The facts revealed by such examination quickly dissipated all
opposition, for they showed beyond doubt that the winters ot
Grandfather’s day really were colder; mean temperatures were
lower and the cold waves more severe and frequent. The
temperature rise is by no means a steady, even one; wide
changes occur with the eleven-year sunspot cycies. But the cold
phase of each succeeding cycle is a little less cold, and each
warm phase is a little warmer.
When we consider what this rise means to us, we come face
to face with a situation emphasized in the last chapter: Man
exists solely because of a fortunate balance of Chemical and
physical factors in his environment. A mere io° F. rise in
tropical temperatures would make life practically impossible for
him and all other warm-blooded animals whenever humidity
accompanied the heat. In my experimental hot room I have
found 90°-9i° F., with 60 per cent. water saturation of the air,
to be the highest level at which warm-blooded animals can live
without a sharp rise in death rate and cómplete loss of repro-
ductive capacity. On several occasions the electric Controls have
failed to operate and temperatures of 97°-98° F. have wiped
out my whole hot-room animal colony within a few hours.
Severe summer heat waves sometimes leave us with an
exceedingly narrow margin of safety even here in middle
temperate America. When heatstroke cases begin to appear in
the hospital, a rise of another 50 F. in air temperatures would
produce a holocaust of deaths. In the summer of 1934, Death
had whole population masses almost within his grasp as
temperatures in middle United States latitudes soarcd past
the ioo° F. level for the daytime maximum. Cattle, horses,
hogs, dogs, birds—all were dying or endangered along with
man.
While a rise of io° F. in earth temperatures would render the
tropical lowlands uninhabitable, a fall of io° F. below present
levels would bring on another ice age and bury large Con-
tinental areas under miles of snow and ice. This happened
several times in the past, blotting out whole species of animal
life. Humanity was then scarce and even in the most propitious
climates led a furtive existence of exposure to the elements.
To-day mankind is numerous and has encroached into the
regions of climatic extremes where existence is sorely handi-
capped. Severe climatic change might well wipe man out in
such marginal zones. Not so many thousands of years ago polar
cold congealed American life well below the Ohio and Missouri
river latitudes, for these rivers marked the Southern boundary
137
of the ice sheet. It is difficult indeed to imagine Kentucky with
Greenland’s icy cold, but such was then the case.
Man’s chief enemies—aside from his own fellow men—are
the innumerable hosts of bacteria and other micro-organisms
lurking everywhere around him. Many bacteria are ffiendly,
performing functions essential for our welfare. The unfriendly
ones are largely those which reproduce and do best at or near
body temperature (98° F.); they thus thrive best in the tropical
moist heat which is most depressive to our own tissue vitality.
Any considerable rise in earth temperatures would thus also
upset the balance between us and our bacterial foes, increasing
their advantages in the struggle. Conditions would become
more propitious for their growth in food and water outside the
body, while our resistance to their invasive attacks would be
still further weakened. Eventual elimination of the human race
may well take place through the attacks of these swarming
billions of microscopie invaders.
A rise in earth temperatures and further outward expansion
of the broad belt of tropical heat would also bring still another
increase in human handicaps. As the B vitamin requirement is
so much higher in tropical heat, we would need a food supply
richer in these elements; but meat animals grow poorly in the
heat and yield meat deficiënt in these vitamin catalysts. The
cereal grains, our other important B vitamin source, also do
poorly in hot climates. So here would be an additional de-
vitalizing factor puliing man down in a world of even moderately
rising temperatures.
Of course, a io° F. change is not likely to occur universally,
but the dangers of such a change will probably exist to a smaller
degree as the earth’s temperatures slowly rise. It has been
estimated that a rise of only 2° F. in over-all earth temperatures
would clear the polar seas of all ice and raise the oceans’ level
about 150 feet. Dr. Arthur P. Coleman of the Royal Ontario
Museum in Toronto has drawn a vivid word painting of the
result: “With a little imagination, one can picture Oslo or
Rio de Janeiro, seaports with high ground in the rear to which
to retreat, as sending palatial holiday cruisers to see New York’s
deserted skyscrapers rising as steep-walled bird rocks from
a shallow sea
Real-estate owners need not worry for the time being, for
this is still a possibility of the distant future. Temperature rises
of two degrees and more have occurred in restricted regions of
the earth but, luckily for us, not for the entire globe as a whole.
Still, these changes in temperatures and in storminess are pro-
138
ducing noticeable effects to-day. They result in marked
alterations in inland rainfall. On the western plains of America,
for instance, deep low-pressure storm centres are needed if'
moisture is to be carried that far inland by air currents from the
Gulf of Mexico and Atlantic Ocean. Periods of heat and
lessened storminess therefore mean an expansion of our desert
areas in the South-west. Early settlers on the plains teil of the
grass being stirrup-high even as late as the middle of the last
century; to-day the erop is scanty and short. Much of this
change may have been due to over-grazing, but reduced rain-
fall and more severe summer heat have also played a large
part.
As I drove from Kansas up through Nebraska and South
Dakota in July of 1934, swirling dust clouds obscured the sun
and nearby landscape, and shifting topsoil buried fences,
buildings, and roads under ever-changing drifts. There I saw
deserts in the making—it was truly a gruesome sight. The soil
of Kansas shows that the plains experienced similar periods of
long-continued drought and blowing topsoil centuries before
there was any cultivation or over-grazing upon which to lay
the blame. No narrow band of planted trees is likcly to halt,
or in any way affect, these major shifts in inland ciimates. They
seem linked rather to the changes in world weather taking place
under fluctuating outside influences from the solar system.
As earth temperatures rise and cyclonic storminess lessens,
rainfall in the Southern and eastern sections of the United
States will tend to become more sharply seasonal in character.
Floods and soil erosion will be accentuated during the rainy
season. Drought conditions through the remainder of the year
will be much less favourable to agriculture than is the present
more even distribution of rainfall. Perhaps our Ohio River
flood of 1937 will pale into insignificance as we plunge another
century or two into the coming warmth.
Dust storms of northern China have for centuries been
carrying loose top soil eastward toward the ocean during the
dry winter seasons. In some places enormous banks of this
fluffy loess fill whole valleys, constituting the predominant
top soil there just as it does in Kansas. During the North China
dust storms the sun may be entirely obscured or just faintly
visible through the swirling clouds. A sprinkle of rain at such
times often showered us with pellets of mud. Dust originating
a thousand miles inland was carried hundreds of miles out to
sea over the Gulf of Peichili.
Americans berated the Chinese for permitting farming
139
methods which made possible this shifting of top soil. But our
own dust storms of recent years have brought home to us the
futility of our puny efforts to hold back the mighty forces of
Nature. Our fertile plains became an American Dust Bowl,
generating clouds of fluffy top soil 1,000-2,000 miles wide which
swept eastward across the continent and out over the Atlantic
Ocean.
I smiled as I saw these enormous dust storms sweep over
Gincinnati, with showers of mud pellets or layers of powdery
clay coating everything in sight. We Americans had been so
sure of our wisdom as we blamed the Chinese people for their
dust storms, floods, and famines. Now they can smile at us as
we experience in a minor way the adverse natural forces with
which they have been contending for centuries. Intelligent
Chinese look upon us as rather raw barbarians, lacking in the
refinements of real civilization and much given to telling the
other person what he should do for his own good. They hope
that another few centuries of living experience may mellow us
somewhat and increase our tolerance of the mistakes others
make when faced with difficult situations. Until recently in our
national history an exuberance of energy and a great wealth
of natural resources had enabled us to make good on our
boastful and egotistic attitude. Perhaps the climatic changes
now apparently brewing will bring to us a degree of wholesome
humility.
You need no longer doubt the validity of climatic change.
Huntington prefers to call it pulsation rather than change,
emphasizing its cyclic character instead of any one-way trend,
and he is quite right.
-
Cyclic fluctuation is the keynote from beginning to end.
Shortest of these cycles are day-to-night variations. Next longer
are weather changes brought by passing cyclonic storms. Then
come the seasonal changes of each year and the more irregular
alterations occurring every few years in an indefinite association
with the eleven-year sunspot cycle. Marked shiftings covering
several centuries have taken place, but the most regularly
recurring ones of longer duration have been the 2,000-year
cycles df alternating cold and warmth in evidence since the last
ice age. Most striking of all, of course, were the alternating ice
ages and interglacial warmth.
This climatic habitat in which we live and by which we are
so dominated is thus seen to be in a most unstable state. One
year we are pushed forward into restless strivings by cold and
storms. The next may bring debilitating heat and physical
140
lethargy. Sometimes there are almost as marked differences in
the intensity of climatic stimulation from season to season or
from one year to another as there are in different regions.
A long summer of severe heat in Cincinnati may leave the
city’s residents with a distinct turn toward tropical characteristics,
but a winter of prolonged cold again prods them into energetic
activity. Our responsiveness to this fluctuating environment
raises several social and economie problems which deserve
careful consideration against the background of climatic in-
fluence here painted. These will be considered in the following
chapters.
chapter 18
CLIMATE, WEATHER, AND WORLD
DOMINANGE
Stormy weather has been held responsible for many
of our respiratory and rheumatic ills; however, atmospheric
turbulence has its good points as well as its bad. Frequent
change gives a wholesome and stimulating variety to life, in-
ducing in people a restlessness which—when coupled with
coolness and a high energy level—drives them on to build sky-
scrapers, set up great factories, and pursue other energetic
activities. There is little monotony, either climatic, mental, or
physical, in such surroundings; while certain types of disease
may abound, health in general is most buoyant and life most
interesting. The men dwelling amid such influences are the ones
who have dominated the world in the past and who have left
their home countries to build empires in distant lands.
Storms sweeping across Indiana were among the most potent
factors influencing my childhood years. To me they represented
the real might of Nature as they came from the South-west to
darken the entire sky. Excitement and sometimes childish terror
acconipanied the thunderous tumult of their passing, while
deepest awe and exultation came over me as I watched the vivid
colouring made by the setting sun against the receding cloud
masses. Even as a boy they interested me by their definite
pattern of approach and passage. Surely, I thought, only the
most supreme and powerful ruler of the universe could keep
harmony and order in the presence of such violent, raging forces.
141
City residents miss much of this closeness with Nature. For
them, with attention focused upon crowded humanity and its
doings, such disturbances only bring inconvenience and inter-
ference with plans. Even the glorious after-coloüring in an
evening sky often goes unheeded.
As I grew older I learned that various parts of the earth differ
greatly in their storminess, that few regions can compare with
the middle-west and western plains of America, and that the
storms do indeed follow a quite definite pattern. Across tem-
perate lands they travel mainly eastward, with the low-pressure
centre preceded and followed by a “high” and cool clear
weather. Warm moist winds rush in toward the “low” centre
and then spiral upward clockwise, being chilled as they rise and
precipitating their moisture upon the earth beneath. Baro-
metric pressure falls and temperatures rise as such low-pressure
centres approach a given locality. Those are the weather periods
which most disturb body function in men and animals. As they
pass on, pressure begins to rise, temperatures fali, the skies clear,
and life assumes a more cheerful aspect.
During peacetime ijiany city newspapers printed daily weather
maps, recognizing an increased reader interest in weather and
the behaviour of the elements. War censorship now prevents the
publication of these maps or the broadcasting of extensive
weather reports, because such information would be extremely
valuable to our enemies in plotting the changes coming their
way. Plans for the dash of the German warships Gneisenau and
Scharnhorst from their Brest berth up through the English Channel
were no doubt based upon reports sent in from scouting planes
and ships out in the Atlantic Ocean. With a period of bad
weather and winter fog in the offing, details of the move were
worked out in such a way that the English were relatively help-
less when they finally spotted the ships through a break in the
Channel fog. Swarms of German fighter planes had been held
in readiness for air coverage just in case the fog shöuld lift.
Accurate prediction depends on a thorough knowledge of world
trends in air-mass movements, and the lefcs the Nazis know
about such trends around North America, the less accurate
will be their timing of strategie moves.
As far as possible, you should familiarize yourself with weather
maps, for they are extremely important in your life. Observing
them from day to day, you can see the “highs” and “lows”
marching across the continent, bringing with them the sharp
alterations in weather which give spice and variety to life. Many
of the high-pressure centres come down from the Canadian
14a
North-west and turn eastward across the Mississippi Basin at
various latitudes, some of them even going down across
Oklahoma and Texas to pass out eastward over the Gulf of
Mexico. Other “high” centres come in from the Pacific coast at
middle latitudes and bring with them less vigorous weather
change.
Not all temperate-zone lands are equally affected by these
eastward-travelling storms; they are probably most vigorous and
reach farthest south in North America. Across Europe they
follow a more northerly course, entering mainly across the
British Isles and countries of West Central Europe. In both
northern and Southern hemispheres they are responsible for the
. storminess of the mariners’ “roaring forties,” but in the south
these latitudes involve relatively small amounts of land surface—
only the Southern half of Chile and Argentina, the Southern
fringe of Australia, and all of New Zealand. South Africa is
little affected.
Storms entering across Europe seem to be dissipated in the
great spaces of Soviet Russia. Siberia has violent weather
changes, but its storm tracks have not yet been plotted. In
eastern Asia less violent disturbances generate on the highlands
of Tibet and Mongolia, then sweep down across China and
Japan during the winter season. Everywhere these temperate-
zone storms are more frequent and vigorous in winter,
penetrating closer to sub-tropical latitudes. In the summer they
become fewer, travel more slowly, and follow a more northerly
course. In North America this seasonal difference means that
the South has stormy weather during the winter, but is blanketed
by stagnant moist warmth through the long summer.
Even in the North, summer storminess is only half that of the
winter.
Another type of disturbance originates over ocean waters in
the outer portions of the tropics, largely between latitudes
io° and 20° and particularly in the Indian and western portions
of the Atlantic and Pacific Oceans. These are deep low-pressure
centres which—and this is important—are not preceded or
followed by corresponding “highs” as they travel westward
over tropical waters. In the Atlantic they lash the West Indies,
Gulf of Mexico, and south-eastem coast of North America,
many of them swerving north-eastward up the coast sometimes
as far as New England. Here they are known as hurricanes.
Over Oriental waters and the Indian Ocean similar disturbances
are called typhoons. From the Pacific Ocean they sweep west-
ward across the Philippines, then turn north up the China coast
143
and out north-eastward across Japan. These tropical storms are
sharply seasonal, occurring largely from September to December
in the northern hemisphere. In the Bay of Bengal they are
particularly violent for this brief period each year.
No stimulation attends the passage of such “low” centres,
since they are not followed by “highs.” Populations lying in
their path are wracked by the falling-pressure effects but benefit
by no stimulating coolness such as comes in the wake of
temperate-zone storms.
Over most large tropical land masses the weather is
monotonously even, with never more than a few degrees of
temperature change from day to day—or throughout the
centuries, for that matter—and with negligible pres6ure variation.
Rains are sharply seasonal; in fact the wet and dry seasons are
the only ones spoken of in tropical lands. This type of weather,
non-stormy and sharply limited as to rainy season, also extends
well outward into certain parts of the temperate zones. It pre-
vails in Mexico and the south-western United States, in the
Mediterranean countries of Europe and Africa, and to a con-
siderable degree in much of China.
Considering North America in greater detail, we find that
storms are most frequent across the northern half of the United
States. Weather changes are most violent on the western plains,
with the sharpest and widest fluctuations in pressure and
temperature as the storms pass by. Farther east the changes are
less abrupt. Daily variations in the maximum and minimum
temperature readings throughout the year give sharp emphasis
to this greater turbulence at Bismarck as compared with New
York City.
Each line on the accompanying storm-track maps indicates
the course followed across the continent by a high-pressure
centre, but it should be kept in mind that these moving air
masses are of enormous size—often 1,500 to 2,000 miles in
diameter—so that wide sections of the country are affected on
each side of the moving centre. The south-western United
States, however, is seldom bothered by the centres sweeping
down east of the Rocky Mountains, even during the more
turbulent winter season. A few of the winter “high” centres pass
down and out over the Gulf of Mexico, bringing freezing weather
even to the Southern tips of Florida and Texas.
One such “high” swept down over the Gulf of Mexico late in
January of 1935 while the ship on which I was Philippine-bound
was travelling up the south-western coast of Mexico. As we
started across the Gulf of Tehuantepec a terrible gale struck us
144
from the north, buffering the ship severely for several hours
until we reached the western edge of the gulf. The ship’s captain
explained to me that such gales were frequent in winter, when-
ever a “high” settled in the Gulf of Mexico. Mountains extend
throughout the length of Mexico except in the low-lying Isthmus
of Tehuantepec, and over this low isthmus the cold, heavy air
of the “high” centre escapes southward to produce gales such
as we encountered.
Storms and the variety of weather changes they bring serve
as foreground details of the environmental picture, while the
more sedate features of climate provide the dominant design
and background. We may be pushed this way and that by short-
cycle weather changes, with our bodily and mental functions
badly disarranged. It is climate, however, which determines the
general energy and vitality level upon which we live. Mean tem-
peratures prevailing at different latitudes out from the Equator
are of profound importance to man, since they decide the ease
with which he can lose his own body heat and hence the rate of
combustion allowed in his tissues.
Tropical lowlands everywhere are blanketed by a continuous
moist heat which makes an active life impossible. Natives of
such regions are sluggish or lazy not as much from choice as
from necessity; if allowed greater ease of heat loss, they soon
become more active. This was well illustrated by the hundred
Philippine women wrapping bubble gum in a Manila factory,
who turned out 30 per cent. more work after the manager
installed cooling equipment to provide a 65° F. temperature
in the wrapping-room.
The tropical blanket of moist heat often extends only two or
three thousand feet above the ground, giving way rather sharply
to cold upper air. It is in this border that clouds form wherever
an upward current carries the moist surface air through into
the cold zone. Going aloft in an aeroplane, you suddenly leavc
the depressing surface heat as you pass above the cloud layer.
Tropical upland regions are thus distinctly more stimulating
than the lowlands, and the natives readily show the difference
by their activity and alertness.
I had not realized just how sharp this contrast might be until
an aeroplane trip transported me suddenly from the enervating
Manila heat up into the mountain coolness at Baguio. From
there I went by car through the Bontoc rice-terrace region and
on up to the Igorot country, where, at 7,000 feet, ice occasionally
formed at night. Up there the midday sun was warm, but
blankets were always needed at night. The natives walked or
145
trotted with quick springy step, were keen-eyed and stockily
built as compared with the more slender, slouching residents
of the hot lowlands.
According to legend, a large group of lepers had escaped into
this mountain region back in early Spanish days and had lost
their disease in the more invigorating mountain atmosphere.
Whether or not the legend has any basis in fact, it is true that
the disease is very much less frequent in the mountain provinces
than among the lowland people. Going back down again into
the Manila heat, I appreciated more clearly what sharp
differences in ease of body heat loss might mean in terms of
human energy and vitality. The Manila people now seemed
well justified in their praise of the Baguio air.
What such differences mean in military terms was shown in
the case of the highland Igorots, who took such vigorous part in
the defence of Luzon when the Japanese invaded the Philippines.
They were also one of the most powerful groups in carrying on
guerrilla warfare and underground activities after Luzon was
lost. As the war continues in tropical countries, such peoples
will undoubtedly continue to make things as unpleasant as
possible for invading armies and they will be able to do so
because of the driving forces of their native climates. It was in
the high Igorot country that the Filipinos carried out the most
active and prolonged resistance to American forces following
the Spanish-American War.
Unfortunately, highland regions within the tropics are not
extensive or capable of supporting large populations. The Andes
Highlands of South America and the Abyssinian Plateau of
Africa offer temperate climates amid the morass of tropical heat,
and on them man has at times done well. No major storm
changes come to disturb their weather, however, or to add spice
and variety to life. People living at Bogota in the northern
Andes give glowing accounts of their climate’s perfection—
never too hot or too cold, always just right—but they also teil
of frequent nervous disorders during the long cloudless months
of the dry season and of an intense desire for weather change.
For them it is often a relief to spend a few weeks down in the
lowland heat.
South America is not particularly blessed, climatically speak-
ing, except for the Andes Highland valleys—where ancient
Indian civilizations reached such high stages of development
before being despoiled by the Spanish conquerors. Only the
Southern half of Argentina and Chile are favoured by temperate-
zone coolness and storms. To be sure, moderate relief from
146
I
lowland heat is afforded in the Brazilian Highlands along the
eastern ooast, but throughout the jungles of the Orinoco,
Amazon, and upper Parana basins debilitating heat holds man
down to a life of tropical lassitude.
As a whole, Africa is in a similar situation. It has little to
recommend it in a climatic sense. Monotonous heat is the
dominant factor from Cape Town to Cairo, unrelieved any-
where by major cyclonic storminess. The Southern portion is
a tableland standing 2,000 to 4,000 feet high with its elevation
giving some relief from the heat, but only the Southern tip gets
much weather effect from the cyclonic storms travelling east-
ward a few hundred miles farther south. Winter brings
comfortable coolness to both Southern plateau and northern
desert, yet nowhere on the continent are conditions favourable
to any great human progressiveness. South Africa is handicapped
least, but its climate has little of the invigoration which pushes
man forward in central latitudes of North America or in West
Central Europe. Through the continent’s equatorial jungles
human existence is held to the lowest possible level by steaming
heat.
In sub-tropical portions of the temperate zones, summer
warmth is fully as enervating as in regions nearer the Equator,
but a welcome relief is afforded by winter coolness. Life goes
on at a more active level during the cooler months, but slumps
back into tropical lethargy as summer heat returns.
Man has his best chance to live a highly vital and energetic
existence in middle temperate latitudes of the earth. Summer
heat is usually brief and interspaced with cool periods, winter
cold is not too great, and ideal temperatures are brought by
the spring and autumn months. Across North America at
latitudes from 350 to 50° these stimulating temperatures push
man into an energetic restlessness and a great impatience with
the slower life of tropical lands. From Cape Hatteras to the
mouth of the St. Lawrence, from Memphis to Winnipeg, and
from Los Angeles to Vancouver, human energy and initiative
rise to the highest level. Frequent storm changes in the weather
and wide seasonal variations leave few dull intervals for
Americans of these latitudes.
Best temperatures for man fall farther nortK.in Europe, at
latitudes of about 450 to 6o°. This is owing to the warming
effect of the Gulf Stream as it flows across toward Iceland, and
also to the more northerly course of the storms as they travel
eastward over the continent between the Alps and Southern
Scandinavia. Temperatures and storminess in the Medi-
147
' I
-
terranean countries are about on a par with those of our
Southern States bordering the Gulf of Mexico. Italy has
much the same latitude range as New England, but its
climate is more like that of Georgia. Most people think
of Tunis and Algiers as located in tropical heat—and so they
are—but their latitude differs little from that of St. Louis or
Washington.
The Mediterranean region receives a moderate number of
Atlantic storms during the winter months, but depressive heat
rules constantly throughout the long summer just as in our
States on the Gulf of Mexico. Across West Central Europe, on
the other hand, storms coming in over the Gulf Stream bring
frequent weather changes throughout the year, moderating both
the heat of summer and the cold of winter. Toward the east of
Europe weather changes lessen, while seasonal contrasts are
exaggerated; both summer heat and winter cold become more
protracted and severe.
Seasonal extremes of heat and cold also occur over most of
Central Asia. Cold waves penetrate well down from the frozen
northern tundras, but their exit over the plains of India or
China is barred by lofty highlands. As a result, cyclonic stormi-
ness is low over Southern and eastern Asia and the climate is
monotonously regular. During the winters we spent in Peking
cold dry winds blew outward from the interior for weeks at
a time, with the barometer standing constantly high. The
winds were reversed through the summer months, as moist
tropical air flowed north-westward toward the superheated
interior. Those were the summer monsoon winds which lay
a blanket of depressing, moist heat over Japan and China every
year. Similar monsoon currents also flow up across India during
the summer months.
All Southern and eastern Asia is thus oppressed by severe
summer' heat, without cold stormy winters to counterbalance.
The result is a human inertia and energy level only slightly
better than the tropics permit. A few storms do generate on
the high slopes of the Himalayas and highlands of Tibet, follow-
ing down the Yangtze Valley and out over Southern Japan.
These help make the upland portions of China’s Yangtze Valley
one of the most stimulating parts of eastern Asia.
Southern Australia and New Zealand are among the earth’s
most favoured regions so far as climatic effects directly upon
man are concemed. Summer heat and winter cold are moderated
by nearby oceans; cyclonic storms bring ample weather variety
at all seasons. Health hazards of winter are much less than in
148
the northern United States, where severe cold and the year’s
most intense storminess bring a sharp peak in respiratory
diseases and heart failure. Central Australia, except along the
eastern fringe, is very sparsely inhabited; and in the north,
tropical heat exerts its typical effects. Man’s progress in Southern
Australia during the last century has been astounding, but the
favourable land area is so small that no really large population
mass can ever be properly supported. On the streets of London
one has difïiculty in differentiating the Australians from the
Americans or Canadians except by their speech; all have that
springy step and keenness of eye found only in people from
really invigorating climates.
Truly favourable climates are thus seen to be limited to only
a few areas of the earth and to perhaps a third of its human
population. North America has the largest and most in-
vigorating of these regions, with West Central Europe a close
second. It is probably not by chance that people of these two
regions so dominate world affairs. In them energy and initiative
run high, combined with a restlessness which is forever seeking
new outlets of expression. At the opposite pole of human
energetics lie the broad expanses of tropical lowlands. In them
another third of the earth’s population is held captive by the
insurmountable difïiculty of losing body heat. This third of
mankind seems to exist only for exploitation by the energetic
third. In between lie the people of the middle third, living under
climates which hold them to a neutral course. China, Southern
South America, South Africa, and the Mediterranean countries
seem destined to pursue a middle course in human affairs. As
for Russia and Japan, these nations are at the peak of their
military successes—one in holding off and then driving back
supposedly invincible Nazi armies, the other in sweeping rapidly
throughout the Far East and toward India. But only time can
teil whether they will have sufficiënt climate-given energy to
keep up their successes.
The North American and European stimulating areas are
also blessed by a wealth of natural resources for man’s use in
his ceaseless activities. Not content with their home resources,
however, these energetic people also reach out to exploit the
earth’s natural wealth in other regions where the native resi-
dents are too listless to do so themselves. World dominance is
thus firmly based on the driving force of climate. Were the
storms of Central Asia suddenly shifted across the plains of
China, the people of that great nation would in all likelihood
become more prominent in world affairs, make better use of
H9
their own great natural resources, and drive the Japanese out
of their country in short order.
chapter 19
THERMOMETERS AND HISTORY
JVEVOLUTION and conquest have always been considered
to spring from the deep inner urgings of people: in the one case
from the desire for freedom from tyranny and in the other from
the desire of a few men for power. Such is really the case, but
the development and growth of these urgings are linked in
a most surprising fashion to the rise and fall of the mercury in
thermometers. Stormy cold has driven oppressed people into
open revolt time after time, just as enervating heat has had
them pliant under the oppressor’s heel. Group after group of
the world’s people have been pushed out on to the roads of
conquest and expansion by optimal climatic conditions, only
to be halted or forced back into oblivion again by less favourable
temperatures. History’s most vivid example of this is frequently
pointed to to-day because of the Nazis’ experiences with Soviet
winter and Soviet man-power; I refer to Napoleon’s attempted
conquest of the vast Russian nation.
The French military leader, turning back in 1812 from his
unsuccessful attempts to invade England, began mighty
preparations for conquest of the one Continental power still
beyond his grasp. Little did he realize that the intense summer
heat and benumbing winter cold of the Russian plains would
offer a more effective obstacle to his ambition than any human
force which had yet opposed him. Prevailing westerly winds
coming in from the Atlantic Ocean provide western Europe
with an equable climate—cool summers and mild winters. In
Russia, on the other hand, summers are often severely hot and
the winters long and cold.
The Grand Army with which Napoleon began his invasion
was a motley mixture, drawn from all the countries of Europe.
None too well welded together, it was by no means the compact
striking force he was accustomed to using in his campaigns of
conquest. Quick manoeuvres and surprise blows were his chief
150
battle assets, but this army was inclined to be cumbersome and
sluggish. With it he crossed the Niemen River on June 24-th
(1812) to begin his most disastrous venture.
No sooner was he on Russian soil than his army became
enveloped in the first severe heat wave of that fatal summer.
Men died of heatstroke by the hundreds, while it is said that
fully a third of his cavalry mounts were lost in the first ten days.
Green forage was supposed to have produced the colic by which
the horses died, but the same heat which killed the men was
more likely responsible, for colic often accompanies heat
prostration. Mobility for an army in those days depended upon
live, healthy horses; without them the transport of equipment
and supplies bogged down and the quick-striking cavalry lost
its value. Not for Napoleon were the oil-burning monsters of
Hitler, which provide unlimited horse-power regardless of
weather—as long as the oil supply lasts.
Napoleon’s first brush with the Russians disclosed the dis-
astrous effects of the ten days of heat. Both men and horses
moved sluggishly, causing failure of his battle strategy. Time
after time through the summer this loss of mobility in his army
permitted the Russian forces to escape the traps he set for them.
The Cossack ponies, on the other hand, were inured to such
weather and allowed the Russians to harass Napoleon’s forces
without often being pressed into pitched battle.
To-day we know that severe heat quickly devitalizes people
and animals, lowering their internal combustion rate, reducing
the amount of energy available for action, causing the blood
pressure to fall and the individual to become in every way more
like the easy-going tropical native. The heat did far more during
that summer to drag down Napoleon’s forces than did Russian
arms. Weakened by the long summer, he finally came to actual
defeat on the field of battle and began his ill-fated retreat back
to the Niemen. Benumbing Russian cold then came in November
to complete the destruction of his Grand Army, turning the
retreat of his ragged forces into a pitiful rout from which only
a handful survived. It was severe heat which began the ruin of
his Russian venture and freezing cold which gave it the finishing
touches.
The hand of temperature has been evident at other times
through human history. People have rebelled against despotic
repression during years of cold and have been more inclined to
yield to the grasping power of tyrants when prolonged warmth
has drained away their vitality and energy. The French Revo-
lution itself had this temperature basis. Thermometer records at
151
Paris are not available for the eighteenth and first half of the
nineteenth centuries, but at Zwannenberg (less than 300 miles
north) monthly means are on record back to 1743. During the
34 years from 1750 to 1783 only 8 scattered years had
mean annual temperatures below normal, and in each by
only a fraction of a degree. In 1784, however, there began
a prolonged cold period which reached ap. all-time low in 1789.
It was in this year that the French Revolution broke out. For
the 33 years beginning with 1784, only seven intermittent
years had temperatures above the average level and then only
slightly so. Thus the French Revolution and period of
Napoleonic conquest took place in the only period of pro-
longed cold in almost a century.
In 9 of the 12 years following 1816, however, warmth
again prevailed. Most of the liberties won during the revo-
lution were lost in these years of shift back toward despotism.
Severe cold and storms returned again for a brief stay over
Europe in 1829 an^ early 1830, which was followed by an
outburst of revolutionary activity over almost the whole
continent. Vigorous but short-lived revolts occurred from
France to Poland. Warmth quickly returned to quell their
ardour, however, with only one year in the next 17 below
normal. Again in 1848 a year of severe cold and storms caused
smouldering discontent to flame forth into another wave of
uprisings over the continent.
The history óf temperature effects antedates by many
centuries the invention of the thermometer and the .existence
of carefully kept scientific records. The high civilization of
early Babylonia flourished at the head of the Persian Gulf
from about 2900 to 1750 b.c.; that of Troy rosé about 2500 b.c.
and declined a thousand years later. The period from 2500 to
1500 B.c. coincides with one of the millenniums of cold men-
tioned in a preceding chapter. It was followed by prolonged
warmth during which little of note was accomplished by man.
About 750 b.c., however, the Assyrian Empire blossomed
forth (750-612) followed by the Second Babylonian Empire
of the Ghaldeans (612-538 b.c.) and the Persian Empire
(53°~33?b-c.)-
The rise of early Greece also began to gain headway about
750 b.c., with her golden age continuing to 390 b.c. Macedonia
rosé to the north as Greece declined, and slightly later Rome
took over leadership from a still more northerly climate. There
were thus two millenniums of ancient grandeur: In the first,
civilization reached its highest development well south on the
152
Persian Gulf and in the southem iEgean Islands; in the second,
high tide again returned to the people around the Persian Gulf,
but important developments also took place farther to the
north-west—in Greece, Macedonia, and Italy. Each of these
cold periods of high tide in accomplishment were followèd by
centuries of stagnation and confusion during which man seemed
unable to make any real headway. The last of these periods
of heat and futility has aptly been called the Dark Age.
Frigid surroundings are as inimical to human accomplishment
as enervating heat. With the prolonged warmth starting in the
fifth century a.d., the people of central and northern Europe
began a wild ferment of activity. Relieved of the benumbing
cold which legend records for preceding centuries, they now
multiplied rapidly and pushed southward and to the west in
ever-increasing numbers. They early battered down the gates
of Rome and overran the broad empire Caesar’s legions had
conquered. Even the people of Scandinavia blossomed
forth during the warmest centuries of this period, sending
forth the Norsemen and Vikings to conquer and colonize the
coast of Europe as far as Italy and westward to the New
World.
Optimal temperature conditions seemed to prevail farthest
north during the ninth and tenth centuries, for it was then that
the people from Scandinavia colonized Greenland and Iceland
and left their mark on so many points along the coast of Europe.
During this period wave after wave of immigrants from northern
Europe settled in the British Isles and helped give the population
its present varied character. As tempcratures began lo recede
agaiq in the later* Dark Age centuries, the exodus from northern
Europe slowed down, returning cold subdued the Vikings, and
other Powers slowly emerged in middle European latitudes.
Another permanent north-westward shift had taken place, how-
ever, for in the new cold epoch vigorous young nations of central
and western Europe took over from decadent Mediterranean
peoples the torch of civilization.
The pathway of Atlantic storms, which in early times was
down the Mediteranean basin and on across Asia Minor,
shifted far northward to Scandinavia in the warmth of the
Viking centuries, and then settled back across the British Isles
and west-central Europe for the centuries since the time of the
Renaissance. Early in the sixteenth century nations under its
influence began a remarkable period of exploration and con-
quest into all the far corners of the earth. They ruthlessly
exploited any wealth found and later started colonies which
153
grew rapidly into new centres of population. Historical develop-
ments of this last cold period have dealt predominantly with
the doings of people living in the cooler half of the temperate
zones.
Asiatic history, although less well studied than that of Europe,
has shown similarly timed undulations. Vague records of high
developments in Southern China coincide in time approximately
with the early civilizations at the head of the Persian Gulf,
4,000 to 5,000 years ago. Advanced civilizations existed in
Siam, Indo-China, and India during the early Greek period,
although their architectural remains stand to-day in an en-
vironment of people submerged in tropical lethargy. The Great
Wall of China was constructed through the centuries of Roman
decay in the West to hold back the increasing pressure of
northern Asiatic barbarians. Shortly after the period of Viking
conquests in Europe, Mongol hordes swept down over China
from the north much as the barbarians of northern Europe had
somewhat earlier harassed the Romans. The celebrated Ming
Dynasty brought China one of her golden ages at about the
same time the Renaissance and revival of learning awakened
European peoples.
The sway of temperature, so evident through the intermediate
and more distant past, has again come into prominence in
recent years. Rising warmth over the earth is upsetting the
comparative equilibrium recent generations have enjoyed.
World power seems to be embarking again on its course toward
more northern regions, with the two greatest of the northern
giants now locked in deadly struggle for supremacy.
Personal liberty and the democratie way of life reached a high
peak in early Greece; they were lost in the autocratie despotism
of the Dark Ages, but achieved a slow recovery following the
European Renaissance. It was perhaps at the time of Wilson’s
visit to Europe in 1920 that the democratie ideal of personal
freedom reached its widest acceptance. Self-determination of
national groups and the right to a representative type of govern-
ment was insisted upon by Wilson as a basis for future world
security. For a while it looked as though real altruism
might be given a chance in world affairs through the
acceptance of these principles and establishment of the League
of Nations.
This optimistic high tide soon passed to ebb, however, as the
rise of one dictator after another indicated a very evident turn
back toward despotism. The turn gained initial 'momentum
during the post-war years of European upset and economie
154
depression, with unseasonable warmth widely prevailing. Con-
ditions steadied down through the more prosperous and colder
last half of the decade. Even more excessive warmth began in
1929, however, initiating the severe and prolonged economie
depression which held the whole world in its grip for several
years. With the discouragement of these hard times, people
again seemed willing to listen to the glowing demagogie promises
of would-be dictators.
It was during this period of severe ebb-tide in the morale of
western nations that Japan thought she saw her chance for
imperial expansion in the Oriënt. Her great dream of empire
had blossomed under the stimulus of subnormal temperatures
many years before. Nipponese thermometer records go back
only to 1879 (at Nagasaki). Up until 1899 temperatures there
were above the long-term average, but from 1899 to 1914 every
single year was colder than normal. During this period she embarked
upon her career of imperial expansion, fighting Russia for
control of Southern Manchuria and in 1914 grabbing all German
possessions in the Far East. Some of the latter she was forced to
give up in the Versailles peace settlement. Again in 1925 she
demanded valuable rights and concessions in China, but was
baulked by vigilant Western powers.
-
But two years after the economie upheaval—seeing all the
Western nations preoccupied with their own domestic troubles
which had ridden in with the heat beginning late in 1929—the
Japanese considered the time ripe for further expansion. This
time they took over the whole of Manchuria, with a watchful
eye on the reaction of Europe and America. America was for
prompt and positive action, but not so with France and Britain.
Quick to take advantage of their uncertainty, Japan procceded
to overrun province after province in‘China. She met little
real opposition from the Chinese until she began an invasion
of the Yangtze Valley. There she encountered people much more
energized by. the storms sweeping down from the highlands of
Tibet. By hard fighting she finally conquered the lower and
middle Yangtze Valley, but beyond that she was been unable
to go.
By driving the Chinese westward up into the highlands of the
interior, Japan has probably performed a great service for her
enemy. The Chinese army and tens of millions of the most
Progressive inhabitants of the Coastal cities have thus been
pushed back into a much more invigorating climate. The
Chinese are a tenacious, ingenious people and, under the
stimulus of Chungking’s climate, are rapidly developing the
155
resources of that upland region. Much of the country’s under-
ground wealth lies there still untouched. Perhaps China will
become awakened for another golden age by this forced migration
of her most intelligent and capable people into the more ener-
gizing interior.
Here the hand of temperature is affecting the course of history
still in the making. Instead of ruining China by overrunning
her rich Coastal provinces, Japan may instead have provided
just the stimulus needed for the Chinese to lift themselves out
of their long period of apathy. Perhaps it would be wise for the
Chinese to keep Chungking as their permanent Capital and
continue with the development of that rich, more stimulating
upland region.
This factor may play an important role in the future, for the
stronger China becomes the stronger will be the general position
of all the other United Nations. Meanwhile, Japan is still riding
the wave of her 1899-1914 period of energizing lower-than-
normal temperatures. Her rapid progress from Thailand through
Malaya, her conquest of Singapore, her successful invasion of
the Dutch East Indies, and her drive through Burma toward
India have all been examples of an impelling energy which was
at least initiated by great changes in the surroundings of the
Oriental island. That brief period of subnormal temperatures
also had an indirect effect all over the world, for Japan’s seizure
of Manchuria, without effective challenge from the West, con-
vinced her that the time was ripe for a New Order in Asia; it
also demonstrated to the Western dictator nations that they
could go ahead with their own empire-building plans.
Not long afterward Mussolini began trying to mould the
destinies of Italy by adding Ethiopia to his African empire.
Forces even greater th&n II Duce had been taking a hand in
moulding Italy’s destiny for many years; for her long fight for
freedom from the Austrian yoke took place during the period
from 1845 t0 ïÖ6ï, when temperatures at Rome were above
average for not a single one of the seventeen years. The situation
has been quite different in more recent times, however, for
uninterrupted warmth since 1921 has kept the Italian people
pliant under the hand of their dictator. Mussolini’s dream of a
great Mediterranean and African empire has been quickly
shattered by the blows of armies from more invigorating climates.
He lost not only Ethiopia but Eritrea, Italian Somaliland,
and parts of Libya as well, and only the intervention of Nazi
divisions under General Rommel prevented a total rout in the
latter country. Never in modem times have the people of tropical
156
or subtropical climates been able successfully to oppose the
might of more favoured nations.
Soon after Japan had revealed the weakness of the West by
her successful conquest of Manchurid^ the Nazis began arming
for conquest. As the world warmth abated somewhat in 1936
and 1937, the Germans became more aggressive in their ex-
pansion and soon began their forcible absorption of the smaller
surrounding States. The Saar Basin, Austria, and Czechoslovakia
were taken over with only verbal 'protests from the more demo-
cratie Powers. With the seizure of Danzig and the invasion of
Poland, however, France and England finally came to a reluc-
tant decision and declared war. The rigours of actual fighting
now found the Germans well prepared and with vigorous
striking power; France and Italy lay more or less supine, the
British on the defensive. Little obstruction was offered to the
Nazi conquest of the Continent until they turned to eliminate
the Russian forces. Now those two mammoths of the north
are locked in the bloodiest and most destructive war of all
time.
Subjugation of the German war machine, with its complete
dominance of the resources of Europe, will be a difficult task
for the United Nations unless Nazi strength can be sufficiently
drained in the Russian conflict. In any event, it will take a
powerful coalition to crush Germany and prevent her from
attaining that dominant position in world affairs which may be
due—climatically speaking—as earth temperatures proceed
with their long upthrust and the time approaches for another
northward shift in European power.
The Germans came very close to winning their place in the
sun during the first World War, for then as now they possessed
a most vigorous fighting prowess. It may have been temperature
which foiled that first bid for world power, for unseasonable
warmth prevailed throughout Central Europe from June of 1917
to July of 1918. Temperatures in France and England remained
close to normal levels for the period, while that winter in America
was the coldest on record for a half-century. The American
forces surviving influenza and pneumonia in our training camps
during that winter reached the European fighting front the
following spring and summer with an exuberance of energy
which quickly smashed through the tired battle lines to victory.
It can never be known just how much the year of unseasonable
warmth had to do with the crumbling morale of the Central
Powers in the late summer of 1918, or the Western cold with the
final victorious push of the Allied armies. Too many other
157
factors were at work to make an essay of this one temperature
element anything more than a guess.
Truly democratie government has lost much of its repre-
sentative nature through *the recent period of rise in autocratie
dictatorships. Only in the Anglo-Saxon and Scandinavian
countries has the parliamentary form continued to function;
and in most of these there has been a strong shift toward group *
rule, with Labour climbing into the seat of power. The regimen-
tation needed in the long fight ahead against Nazi Germany
will lead us still further along the road to autocracy. Wealth
accumulated through past centuries of expansion is now being
rapidly dissipated on the fields of battle, so the present destruc-
tive struggle may greatly accelerate any downhill trend which
lies ahead.
CHAPTER 20
CLIMATE AND WORLD WAR
Forces beyond human control continue their
irresistible course to-day just as they did through past centuries
of racial history. In the mighty upheaval now going on, any
country which expects to come out on top must give careful
consideration to the effect s these outside influences have on the
health and fighting vigour of its men. War must now be waged
under unique and oftendangerous environmental conditions. New
disease problems are raised, especially in the tropics where the
warmth so enervating to human beings is favourable to the
growth of genus and parasites.
Recognition is being given to these disease problems by the
present active search for new anti-malarial drugs to replace the
quinine formerly obtained from the East Indies and Malaya.
The most recent annual report of the Rockefeller Foundation
tells of the production in its laboratories of 4,000,000 doses of
yellow-fever vaccine for use by United Nations armies engaged
in tropical warfare. Added to the threats from the swarming
disease germs in tropical heat is the discovery—mentioned in
Chapter 2—that the bacteria-fighting white cells in the blood
158
become sluggish and ineffective in hot surroundings. There is
need for intensive and co-ordinated study of what tropical heat
means to man, as well as for further studies into better methods
of handling the infectious agents themselves.
A strong connection exists between vitamins and suscepti-
bility to disease, for people deprived of their normal require-
ments are likely to contract maladies they would never have had
otherwise. There has been much discussion in scientific circies
about the enforced vitamin^starvation of entire populations in
the occupied countries of Europe. Well aware of the vital signi-
ficance of an adequate vitamin intake, the Germans have been
very careful to keep their armed forces and home workers as
well fed as possible. Their first act in a newly occupied country
is to strip it of vitamin-rich foodstuffs, particularly the cereal
grains and animal products which carry most of the B vitamin
supply. The result has been a severe and almost universal
underfeeding of home populations in the occupied lands. More
devastating than the simple food scarcity, however, has been
the vitamin starvation resulting from this German policy.
Many scientists have professed to see in this an intentional effort
by the Germans to weaken the morale, as well as the physical
condition, of the subjugated people and thus to lessen the likeli-
hood of vigorous revolt against the German rule.
Any such vitamin starvation policy is a two-edged sword,
however, for it will mean a markcd lowering in disease resistance.
Tuberculosis, typhus, and a host of other deadly infections will
spring up over the Continent if any such policy is long continued.
Certainly no wise nation would wish this type of disease wall
around its borders or among the people with whom it must
come into intimate contact during future decades. The present
epidemie of typhus raging in parts of Europe may be one of the
first fruits of this German policy. It is hitting most severely in
occupied Poland where the people have been forced into crowded
ghettos in semi-starving condition. Mere concrete walls thrown
around these pest areas failed to keep the disease within bounds,
for now it is spreading rapidly throughout that section of the
continent. Years of similar semi-starvation in Spain gave rise
during the past winter to an epidemie severe enough to prevent
the German forces from using this pathway to African battle-
fields. Disease is a severe and ruthless tyrant, and any people
who knowingly allow it to gain such mastery should prepare to
pay a terrible price for the devastation it will bring.
It is well known that even under normal conditions people
need higher-caiorie foods during extremely cold weather, when
159
the body has natural difficulties maintaining intemal tem-
peratures at the optimum level. American troops in Newfound-
land, Iceland, and increasingly important Alaskan bases require
up to 10,000 calories a day, as contrasted to the average sedentary
worker’s Standard of 2,500 calories. Men in these important
and frigid outposts receive one-third more bacon, and other
fatty meats, as well as 20 per cent. more vegetables. Some
nutritionists doubt whether it is physically possible for men to
eat more than 5,000 calories a day for any continued period.
Some years ago, however, six young American physicians
consumed 6,000 calories daüy for 3 months without trouble or
difficulty—and they were leading a relatively inactive and
sheltered hospital existence at the time. I recall one obese
patiënt whose gluttonous appetite was causing him to ingest
6,500 calories a day, even though he was engaged in almost no
physical activity.
Supplying food to tropical armies presents other peculiar
problems of immediate importance to the welfare of the men.
Although soldiers eat less in the heat, they need food much
richer in the B vitamins to meet their higher requirement. Meats
usually supply the larger part of the needed B vitamins, but
tropical meats are deficiënt in them, so commissary departments
must see that vitamin-rich meats are shipped from temperate
climates.
Fighting men everywhere, but especially in the tropics, need
all the energy they can get from the food they eat. Plenty of
exercise helps to keep vitality high if the diet is adequate. It is
probably safer to give the men in tropical service supplementary
supplies of the B vitamins, however, even though most of their
animal products be shipped from good growing lands. A crude
liver extract or brewer’s yeast is probably the most practical
and concentrated source for daily use. In them, both known and
unknown B fractions are present in fairly well-balanced pro-
portions. Tablets of the purified or synthetic vitamins sometimes
lack sufficiënt quantities of the unknown fractions which
now seem even more essential than thiamin for hot-weather
existence.
There have been definite suggestions that over-dósage with the
purified vitamins can produce toxicity more readily in tropical
heat, even though the requirement is higher than in cool climates.
This is also true of some of the body hormones (intemal secre-
tions). Tropical residents tolerate thyroid extract and insulin
poorly, for very small doses of these two products have been
known to kill tropical patients. Some years ago I reported the
160
tendency of patients in the severe summer heat of Peking to go
into fatal insulin shock from doses considered insignificantly
small in the northem United States. It is safer, therefore, to
provide the vitamins in some crude natural form rather than in
synthetic tablets when giving them routinely to people without
careful watch of each individual. A person is quite unlikely to
take too much yeast or liver extract.
I suppose this talk regarding the value of brewer’s yeast will
lead someone to suggest the advisability of beer-drinking.
Since the yeast grew in beer, why should’t it too be rich in the
vitamins? Perhaps it should be, but it isn’t. Beers and wines
contain practically no vitamins. It is only when the yeast cells
have been digested or broken down that they liberate their
stores of these materials. On that account it would probably
be best to admininster yeast in a slightly cooked form rather than
to give it raw. Boiled for just a few minutes with a quick-thicken-
ing breakfast cereal, it provides a dish which might serve a very
useful purpose in either tropical heat or temperate coolness.
Two of the best cereals for this purpose are oatmeal and wheat
hearts. Both are already rich in the B vitamins as well as in
actual food value. Wheat hearts usually sell as stock food at a
small fraction of the price people pay for less valuable packaged
breakfast foods.
The suggestion of mixing dried yeast with peanut butter and
regular butter as a table spread would also be readily applicable
for use with armed forces in tropical countries. The yeast taste
is thus largely masked by the peanut butter, which is itself also
rich in the B vitamins. Two ounces a day of such a mixture would
cover the extra B requirement in any climate. So also would
a tablespoonful of concentrated liver extract taken twice a
day.
Vitamin requirements are indirectly affected by clipiate, but
the atmospheric surroundings exert another important, less
publicized, and more direct effect on human beings. Never
before in all history have large masses of men been shifted so
abruptly and in such numbers from one climatic extreme to
another as to-day. Japanese troops have fought from the severe
cold of northem Manchuria to the steaming jungles of Malaya
and the East Indies. Germans have engaged in disastrous
efforts on the frigid plains of Russia as well as on the Sahara
sands of Africa. Our own American troops have been scattered
from the polar cold of Iceland to Philippine heat. Fighting
forces of the British Empire are facing almost every conceivable
climatic condition. Quite aside from germ threats, there must
Fcmm 161
also be faced the marked disturbances in body physiology
describëd in these pages, as men shift suddenly from heat to
cold or vice versa.
Fortunately, most of the troops going by ocean convoy to
tropical stations in the Far Eastem fields are subjected to
several weeks of mild tropical warmth on shipboard. They are
thus partially acclimated before they land in the severe lowland
heat of those regions. They should be given regular and
vigorous exercise during the warm ocean voyage to prepare
them for the greater difficulties in heat loss they will face on
landing. German troops destined for African service were said
to have been given daily exercise in heated rooms for weeks or
months before leaving for the front. Long preparation would
not be so beneficial, however, as more intensive* training for
the two-to-four weeks immediately preceding landing in tropical
heat.
Real difficulties are faced by men from stimulating climates
who land in such lowland heat without the benefit of previous
adaptation. These difficulties are greatest for those arriving by
air, for their descent into the surface heat is most abrupt.
Frequent change from severe surface heat to the cold of upper
air puts great stress upon flying personnel engaged in tropical
service. Wherever possible, they should be provided with cooled
ground quarters. They need the active, vigorous metabolism
most readily maintained in cool surroundings.
Just before the outbreak of war with Japan a high-ranking
naval officer, invalided home from Manila, came to me with
a very typical story of troubles arising from too sudden entrance
into tropical heat. He had been on a tour of duty at ports in
the northern United States when he was suddenly called for
a Manila assignment of great responsibility. Leaving his post
in Oregop, he went directly to Manila by clipper plane. He had
previously had many years of tropical service, but most of this
time had been spent at sea where the heat is less severe.
This time he landed directly in the Manila heat and stayed on
land for administrative duties. In rather short order he was
suffering the digestive disturbances and fall in blood pressure
common to heat exhaustion. He tried using cooled office
quarters, but the abrupt contrasts of entering and leaving from
outdoor heat only made his condition worse.
-
Finally invalided home, he was greatly chagrined to be still
on sick leave when war broke out. He is now rather rapidly
recovering and, with knowledge of the proper hygiene of living
in tropical heat, should soon be ready for active service again.
162
There will be many similar cases of heat effects among the
thousands going directly into tropical heat from the winter
climate of the northem United States. Expert as are the Army
and Navy medical men in handling the tropical disease
problems of bacterial and parasitic origin, few of them have
given much thought to these disabling disturbances in body
physiology which arise from the direct effects of the heat
itself.
Tropical fevers and infections of various kinds have taken
a considerable toll among the forces fighting in the lowlands
of the East Indies, Malaya, and Southern China. One of the
most important reasons for Bataan’s fall was the presence of
malaria and other ailments among the courageous American
defenders. So long as drug supplies hold out, however, this toll
is now insignificant compared to what it was a half-century
ago, before modern medical methods of prevention and treat-
ment came into force. Perhaps proper measures to maintain
the highest possible vitality will still further reduce the ravages
brought by these hosts of minute tropical enemies. They are
always to be feared more than those in human form. Japancse
conquest of the East Indian sources for the world’s quinine
supply may prove to be one of her major victories over the
United Nations unless other effective anti-malarial drugs can
be discovered and produced quickly.
The British had always considered Singapore safe from land
attack because of the fever-ridden Malayan jungles; but the
Japanese attention to minute detail seems to have provided
effective protection for their men. Without adequate supplies
of quinine or other good anti-malarial drugs, such jungle
campaigns would indeed have been impossible.
Still more dangerous than sudden transfer of troops from
temperate coolness into tropical heat is a sudden shift in the
reverse direction. Pneumonia, tuberculosis, and a host of other
respiratory infections take a tremendous toll among troops
shifted from tropical homelands into winter fighting on northern
fronts. As we have already noted, in the First WoYld War tuber-
culosis among the African troops fighting in northern France
became almost as acute as pneumonia, running a very rapid
and often fatal course.
It would be disastrous for Italian soldiers to attempt winter
fighting in the polar cold of the northern Russian front. Even
in the much milder weather of the Crimea they are no match
for the more energetic Russians. Germans from the more
stimulating climate of north-central Europe are encountering
163
considerable difficulties in the severe Russian cold. Their
difficulties, however, arise largely from lack of proper dress for
polar temperatures. Garments made of animal skins or furs are
the only ones capable of protecting against those wintry blasts;
only thus can the internal body heat be preserved hgainst too
rapid loss. The Russians have always relied on heavy furs for
winter use and hence have kept themselves well supplied; but
the men of Axis countries have never needed ormsed much of
this type of winter clothing. The Eskimo, in his suit and hood
of skins, is almost immune to outside Arctic cold.
Thus we have at least a part explanation of the vigorous
Russian offensive against the Germans, who froze arms and
feet by the thousands in the enforced winter fighting. The
German General Staff foresaw this danger and urged the
formation early in November of a winter defence line with
heated living quarters. Hitler gambled on paralysing the
Russian forces by a knockout blow before winter closed in.
His gamble backfired and his unprotected troops paid a terrific
price in their enforced activity at sub-zero temperatures. It was
this same catastrophe which overtook Napoleon, after he had
dallied too long on the Russian plains, with his troops in-
adequately clad for the cold of a Russian winter. Present-day
tanks and aeroplanes may be immobilized as the bitter cold
freezes their lubricating oils, but the shaggy-haired Russian
cavalry pony is then in his element.
In a country like ours, with marked climatic differences
between northern and Southern sections, it would seem wise to
use northern troop units for garrisoning Newfoundland, Green-
land, and Iceland, or for active fighting in northern Europe or
Asia. Troops of Southern origin, on the other hand, would be
better adapted for service in tropical heat. Training of the
present army has been conducted largely in camps located in
the south or along the Pacific coast. This undoubtedly has
lessened the respiratory disease hazard, and the Southern
summer warmth has partially prepared the boys for facing real
tropical heat; it does not, however, fit them so well for trans-
portation to cold fighting fronts.
In returning ‘the sick and wounded home from tropical
fighting fronts, careful consideration must again be given to
climatic and weather ‘effects. They face severe respiratory
disease hazards if brought directly into the cold and storms of
a northern winter. The non-stormy South-west offers the ideal
climate for their recuperation; several base hospitals and large
convalescent units should be established there. Men from
164
colder regions of warfare can safely be sent to treatment centres
in other parts of the country.
At the close of the war, men who wlll have spent many months
fighting in tropical heat should be demobilized with care. Great
distress and a widespread epidemie of respiratory disease might
result if they were returned en masse to their northern homes
during the colder seasons of the year. It has been suggested that
the ravages of the terrible influenza and pneumonia epidemie
of the 1917-1918 winter were perhaps made much worse by
the thoughtless transportation of tens of thousands of Southern
draftees to northern cantonments.
Whatever places become future battlegrounds—whether it be
Ceylon, Madagascar, Dakar, Alaska, or Arctic regions near the
northern supply route to Russia—it is apparent that special pro-
vision must be made for troops who are shifted from temperate
zone climates to far different surroundings. This, to be sure, is
only one of many problems facing the world’s military leaders.
But it is an especially important problem, for it involves the
efficiency and morale of the fighting forces—and the war will
be won by soldiers who are as efficiënt and as high in morale
as possible.
Recently there occurred one of the most impressive demon-
strations of the part climate is playing in the fighting melee of
to-day. The eastward onrush of Rommel’s armoured force
across northern Libya and Egypt—coming at a time of year
when it was maintained that severe desert heat would render
tank warfare impossible—is now rumoured to have been made
possible by the use of air-cooled tanks. The Allies had con-
sidered such air-conditioning, but had discarded it as not
feasible because of the tremendous weight of the cooling equip-
ment involved. Some time ago I suggested the use of the
radiational cooling scheme described in Chapter 15, since it
would provide insulation against outside heat as well as cooling
of the tank occupants with a minimal mechanical load. Military
authorities are considering the matter, but it now seems certain
that American Science will have to join more closely with
industry and take a direct part in the carrying out of the war
effort of the United Nations.
165
CHAPTER SI
MIGRATION FOR HEALTH
The case of Mr. X in Chapter 8 was one example of
the advice which may be given in answer to the query, “Where
is the best place for me to live?” This question has been put to
me time and again by persons learning for the first time of the
climatic and weather dominance over their lives. For the
chronic sinus trouble of Mr. X I advised permanent migration
to the South-west, but other climatic regions also have their
good points. Obviously there can be no single answer, for much
depends upon the person’s physical condition and what he
wishes in life. If he seeks healthful contentment and real pleasure
in living, then the ideal climate will be such as the American
South-west offers at 4,000-5,000 feet elevation, or at still higher
levels farther south in Mexico or the Andean highlands. There
moderate stimulation keeps alive one’s interest in life, without
the impatience and boundless enthusiasm which make existence
in colder, more stormy regions so irritating and unsatisfying.
If it is a life of indolent, effortless ease he desires, he should
head for tropical heat where that kind of existence prevails
naturally. But for a life of accomplishment and activity, of keen
competition and initiative, of restless energy in both brain and
body, let him choose the stormy climates of middle temperate
lattitudes. If such be his choice, however, he should be prepared
for a life of strife at every turn—strife in home relations and
discipline, strife in business, strife in public and international
affairs, strife in old age, and strife even in trying to hold death
at bay.
The stresses of northern life, however, give evidence of being
serious health factors, particularly for people who have passed
middle age and lost the resiliency of youth. Cold weather
bothered them little through their younger years, but with
advancing age they chili more easily and meet sudden tem-
perature changes less well. The slower, easy life of warmer
climates exercises more and more of an appeal to these people
with each passing year, and midwinter sees those who are able
heading southward. The automobile trailer was originally
166
developed to meet the needs and desires of these winter migrants
to the sunny Southland. lts success with them soon led to its
widespread use for family travel of all kinds, but it still remains
predominantly a means of north-south seasonal migration.
Like the sap in a mighty oak, automobile trailers begin to
leave their northern outposts with the first autumn frost.
Trickling along the roads at first singly, then in increasing
numbers, by Thanksgiving time they flood the main highways
to the South. They line up by the thousands in Florida’s regi-
mented trailer parks through the winter months, their carefree
occupants basking in that delightful winter atmosphere. Early
March finds them moving back northward with the robins,
fanning out in all directions to reach their New York, Michigan,
or Minnesota homes for the opening of spring. There they stay
from the time the leaves open until they change.colour and
flut ter to the ground in autumn.
Development of the trailer seemed for a while to offer
Americans as nomadic a life as they might wish. People in their
fifties and sixties quit struggling against the rigours of northern
winter life, rented or sold their houses, and took to a trailer
existence. South in winter, north in summer—they were then
as free as the birds to choose the temperature of their environ-
ment.
Younger couples by other hundreds of thousands were forced
from their homes during the long period of economie depression
and by widespread droughts in the plains States. These hordes
headed westward, as have nearly all migratory masses since the
beginnings of the race in Central Asia. Constant streams of them
poured into California and the Pacific North-west, with the
whole family and a few household belongings piled into the
most ramshackle conveyances imaginable. Without funds or
chance to work, these wanderers soon swamped all relief
facilities in the Coastal States. Camping in any available spot,
but especially along the mountain streams, by their unsanitary
life they raised real disease hazards for the surrounding com-
munities and forced Govemmental attention to focus on their
problems.
For several years West Coast authorities struggled with the
handling of this nomad population without much success.
Booming war industries have now provided temporary employ-
ment and means of support for many of them, but their basic
peacetime problems still remain. Similar medical problems arise
from the thousands of migratory labourers who follow seasonal
employment northward from early spring to late autumn, with
167
no home except the tents or trailers they and their families
' occupy. From strawberry-picking in February, they move north-
ward by easy stages with the ripening of the crops, both in the
East and in the Far West.
States and smaller settled communities have found it necessary
to put the same restrictions and obligations upon these homeless
migrants as they do upon their own permanent inhabitants. In
a sparsely settled country few hygienic restrictions are needed,
but when many millions of people are concerned, careful watdï
must be kept of the factors which promote the spread of disease.
The trailer and free movement of families from place to place
threatened to become such a menace, in addition to creating
difficult school and public service problems; hence rules and
regulations are gradually being worked out, again placing on
these people their proper responsibilities as members of a civi-
lized society. The complete freedom thus seemingly offered by
the trailer in its early years is gradually being r^placed by the
cares of a settled life, as indeed it must in any densely populated
land.
In spite of these problems, however, America is on the move
again. Perhaps because of our driving climate, we have never
been a people to strike deep roots into the soil of a given locality
like the more fixed populations of the Old World. Few of our
homesteads are handed down for generations within the same
family. Being thus somewhat nomadic by dispositibn, we should
be well able to avoid any climatic or weather situation not to our
liking. We have at hand the means and the disposition: it only
remains for us to acquire the knowledge as to when and where
we should move.
There are several large classes of northerners who would
benefit from seasonal or permanent southward migration. The
largest of these includes the millions of elderly people whose
tissue fires have pretty well burned out or become choked with
the clinkers of degenerative disease. With their arteriosclerosis,
diabetes, chronic nephritis, heart troubles, and a host of other
chronic ailments, they are no longer fit for the physical struggle
it takes to survive the stormy cold of northern winters. Younger
and more resilient individuals match the rigours of winter with
a heightening of their own vitality and bodily vigour, but the
winter battle is too strenuous for the brittle oldster. With his
lowered rate of internal heat production, he chills easily; and
with each chilling his already sluggish white blood cells become
still more inactive, leaving him especially susceptible to pneu-
monia, bronchitis, and other respiratory infections.
168
Untold numbers of elderly northemers have found benefk
from wintering in the South or from moving there for permanent
residence. Many others should realize the value of such a move
in giving them a more prolonged and healthful existence for
their declining years. Day-by-day activities in Southern warmth
follo\V a less energetic pattern and fit better the slower combustion
rate of body tissues in the later decades t>f life. The energetic
northemer finds it difficult to keep up his working enthusiasm
after a few months in tropical warmth. Money-making schemes
seem less enticing when the body heat generated in their planning
and executkm is difficult to dispose of. So the retired northerner
who finds icfle life such a bore should go south and let the warmth
fit him to a slower tempo of affairs.
Such advice is particularly appropriate for any person whose
arteries have hardened under the stress of northern life and
whose heart has narrow limits to the work it can perform.
Such people, and their diabetic brethren, would add years and
increased comfort to their lives by getting away from the in-
vigoration of cool climates. The farther they move into tropical
heat the better it will be for them. Southern Florida, the Browns-
ville district of Texas, or Southern California—these should be
their havens of refuge within the borders of the United States.
Northern Florida and the northern Gulf coast offer a delightful
climate for winter vacationing, but only during the summer
months is their warmth sufficiënt to subdue an active body
metabolism.
Migration to Cuba, Puerto Rico, or Panama would be still
more effective, but few Americans care to go beyond the borders
of their homeland for permanent residence. Wintering in some
tropical country would be helpful, but the return to northern
homes could not safely be made before April or May, when ail
danger of cold weather has passed. Several weeks or months
of tropical warmth would bring a sharp lowering of the body’s
resistance to respiratory infections, leaving the returning in-
dividual overly susceptible to colds, bronchitis, sinusitis, and
pneumonia.
The millions of people affiieted with repeated respiratory
troubles each winter form another large group who would benefit
greatly from permanent or seasonal change of climate. They
should not seek tropical warmth, however, but rather a non-
stormy region with moderately invigorating climate. Within
the United States such climatic conditions exist only in the
South-west, within about 200 miles of the Mexican border from
El Paso to the Pacific coast. Cyclonic weather disturbances
169
practically never bring their sudden changes in temperature
and barometric pressure to that region. Peoplc living there are
in the main rcmarkably free from the respiratory and rheumatic
troubles storm changes bring elsewhere.
Tucson, Phoenix, Albuquerque, or other valley cities of that
region offer delightful wintering spots for respiratory disease
sufferers, but for year-round residence a more elevated or
slightly more northern location should be chosen so as to avoid
the severe daytime heat of the summer months. The Southern
California climate is also good, except along the immediate
Coastal fringe where the constant inshore winds laden with ocean
moisture exercise a bad influence. This ocean mafeture is es-
pecially bad during the midwinter months, when thick fogs
oftcn prevail. A permanent residence for sufferers from respira-
tory disease should thus be located well back from the coast
(30 miles or so), and preferably 2,000-3,000 feet above sea-level.
The South-western climate is the best America has to offer people
whose lives are made miscrable by one respiratory infection
after another through the stormy winter months. Similar benefits
are offered European sufferers by the mild climate of the
Meditcrranean Basin and northern Africa.
Many persons have found their sinusitis or chronic bronchitis
made worse instead of better by a midwinter sojourn in the
Caribbean or Gulf toast regions. This happens for two reasons.
First, the warmth lowers their tissue vitality and allows the
infections they carry in chronic form to become more active or
acute; second, hurricane-type storms sweep westward across the
West Indies through the autumn and early winter, bringing
somewhat the samc influences on man as do the cyclonic storms
of northern winters.
-
Removal to the South-west is most imperative for people
attacked by acute rheumatic infections of the joints or heart
valves. Unfortunately, these attacks are most frequent among
poor people who are bound to their place of abode by the iron
chains of poverty. Real tragedy often faces a child in whom
rheumatic infection begins, with one attack after another
bringing increasing damage to the heart and finally ending in
complete invalidism or death. Transfer to the non-stormy South-
west usually prevents new attacks and allows gradual repair of
the heart damage.
Economie handicaps unfortunately prevent most people from
availing themselves of the benefits such changes of location offer.
Here would seem to be a logical avenue for federal action in the
interests of the public heaith. Establishment of convalescent
170
colonies or health farms in irrigated valleys of the South-west
might allow many people now incapacitated by respiratory or
rheümatic infections to regain their health and again become
self-supporting. The home communities of many such patients
would find it less expensive to finance migration than to pay for
the repeated hospitalizations required if the victims live on
where their disease progresses from bad to worse.
A more enlightened public-health attitude would also aid
thousands of elderly people to move from the north to less
energizftig Southern regions where they could lead a more
comfortable existence and at the same time be fed and cared
for more cheaply. America is only just beginning to consider
the problems of its ageing population. As their numbers become
still more numerous in the decades ahead, and the public con-
science becomes more aware of their Handicaps, perhaps steps
will be taken to aid them in finding Southern homes for their
declining years. Many will not care to leave family and friends
for such a move, but the possibility of doing so should not be
limited to the well-to-do as it now is. A man who has spent his
life labouring with his hands in the nation’s workshops has earned
the right to a comfortable old age just as much as has the well-
paid executive who directed his labours. Somc travellers have
reported Russia as being far ahead of us in such matters, with
numerous health resorts and convalescent colonies for working
people dotting the Black Sea shores.
Hay-fever sufferers who fail to obtain relief from desensitizing
injections often find removal to another locality a great help.
After discovering the'particular pollen to which they are scnsitive,
they should seek a region where that plant does not grow and
stay there during its blossoming season. Owing to the desert
conditions generally prevailing in the South-west, the air there
is usually free of pollen, and that region is a favourite resort for
hay-fever victims. Injection treatment at home is less expensive
than yearly migration, but it usually must be repeated just
before each hay-fever season. Many such sufferers choose to
take their annual vacation at their season of trouble and go
away to an atmosphere free of the particles which bother them.
Still another class to whom the non-stormy South-west should
appeal is the type so very sensitive to change in barometric
pressure. For many people the days of sharply falling pressure
mean real misery—headaches, migraine attacks, melancholie
moods, restlessness, and hyper-irritability. Often it is the lining
mucosa of the nose and sinuses which is sensitive to weather
change, puffing up with the approach of stormy weather ter clog
the sinus openings and bring acute discomfort. Many so-called
sinus headaches arise on this basis. For such weather-sensitive
people the South-west offers great benefits. Some of them arè so
extremely susceptible that they are affected even by the minute
pressure changes occurring at Los Angeles, but for most that
climate affords almost complete relief.
What about migration for the southerner? His greatest benefits
come from avoidance of the depressive summer heat. Nearby
mountain or seaside resorts serve him best. To escape the heat
by going northward up the central trough of the contirient he
would need to travel almost to the Ganadian border, else he
might encounter summer heat even more severe than at his
Gulf coast home. Southerners or tropical residents suffering
from low vitality and heat debility—children especially—often
obtain marked benefit from a few weeks in northern coolness.
They should take care, however, to leave the North before the
winter storms begin, else they will encounter severe respiratory
disease risks. Among the thousands of labourers and draftees
who came up from the Southern States during the First World
War, winter cold and storms exacted a truly terrible pneumonia
toll.
The only change of climate possible for most people must be
squeezed into their year’s brief vacation period. When should
this vacation be taken, and where should they go? The answer
will depend upon the type of person concerned. For the energetic,
dynamic type of northerner, a January or February vacation
in Southern warmth is best, since it gives a restful break in the
long period of winter stress. Such people should stay on the job
during summer warmth so that the heat can slow them down
somewhat. That is their yearly chance at the biologie rest they
stand in great need of, for their greatest health dangers arise
from the breakdown and exhaustive diseases such as heart failure
or diabetes. With their high metabolic rate, they usually dislike
summer heat, although they need its calming effect.
Many less dynamic northerners find themselves slumping into
tropical lethargy in summer heat, or perhaps they develop
symptoms of mild heat exhaustion—low blood pressure, weakness,
loss of appetite, lassitude, etc. For such people vacations had
best be taken in a cooler locality through the worst of the summer
warmth.
Finally, there are those who do poorly in both winter cold
and summer heat, those exhausted neurasthenics or people with
a constitutionally subnormal physique who need to migrate with
the birds—north in summer and south in winter. Such people
172
are fortunate indeed if they possess the means to finance travel;
otherwise they make themselves and everyone around them
miserable by wanting high indoor temperatures in winter and
by constantly reminding everyone of how hot it is in summer.
Their distress is unquestionably real and is often best relieved
by intensive B vitamin therapy to reinforce their tissue com-
bustion processes.
The day may not be far distant when our knowledge of nutji-
tion will enable us to maintain a high energy level in tropical
heat. Propei* use of the B vitamins—the combustion catalysts—
may make this possible, liberating tropical residents from the
lethargy which has smothered all initiative up to now. The boon
to mankind would be great indeed if the material wealth and
productive capacity of tropical lands could be matched with a
more effective energy level in the native inhabitants or in people
migrating there from cooler lands.
One very minor type of migration for health is needed in the
industrial cities of the earth. People should abandon—for
residence purpose—those districts where atmospheric pollution
raises severe respiratory disease hazards. Movement to homes out
in cleaner suburban air will pay high dividends in health. In
such change of location study should be made of local topography
and prevailing wind direction so as to avoid the stream of smoke-
laden air. This outward shifting of city populations has long been
in progress, and has been responsible for destructive shrinkagc
in downtown real-estate values. Smoke and industrial dirt thus
cast their pall over economie values, as well as over the people’s
health. Some day an aroused public will demand that proper
steps be. taken to relieve this wasteful and unsightly situation.
It is true that the great majority of people are not sulfidently
bothered by climatic and weather handicaps to justify the
breaking of long-established business and social relationships
for removal to a different climate; but if all climatic or weather
victims in the North were to re-locate in the South or South-
west, those regions would become densely populated. Florida
could handle millions of oldsters on small plots of land, but much
more irrigated acreage would be needed in the South-west to
support the army of weather refugees who would head in that
direction.
While we as a nation were young and lusty, we gave little
attention to these matters; now that the proportion of elderly
people in the population is rapidly increasing, more thought is
being given to environmental handicaps and the advantages
different regions have to offer. Elderly people started the winter
173
movement to the South, and they will probably be the pioneers
also to other regions. With their waning vitahty they feel the
handicaps most keenly and are often best situated economically
to make the needed change 'of location. People retired from
their life-time occupation, pensioned war veterans, widows left
with enough insurance money or other accumulated wealth for
their support, young people out of college looking for a place
to begin the real business of life, invalids, and many others are
the ones who should give thought to the climatic factor in life
and what it might mean for their health and welfare.
CHAPTER 22
FROM FLOOD TIDE TO BEGINNING EBB
u ver 2,000 years ago the people of early Greece
reached levels of development fully as high as those of to-day
along social, economie, and philosophical lines, but they lacked
the mechanical ingenuity which has brought to us the Golden
Age of the Machine. To-day the machine has so woven itself
into our lives that it completely dominates every phase of
existence. Look around wherever you are—at the clothing you
wear, the books or papers you read, the furniture you use, the
building sheltering you, your means of transportation and
communication, the iood you cat, even the conditioned air you
breathe—all show the work of complicated machinery. Man’s
activities have expanded at an ever-increasing rate through
recent centuries, with the application of an inventive and
scientific genius such as had never before been seen.
During the rapid advance through this astonishing mechanical
age, man expanded also in other ways. His numbers over the
earth more than doubled in 'the nineteenth century alone. He
increased also in his individual stature and came to maturity
at progressively earlier ages. Fathers regularly saw their sons
grow up to tower over them, mothers found themselves looking
upward into the faces of their tall daughters. Not very favour-
able to parental discipline, this having children in their teens
look down upon their parents!
Stature improvement since Revolutionary days has indeed
been remarkable. The soldier of to-day is four inches taller than
174
the private of a hundred and fifty years ago and has more weight
for each inch of height. College student records in some American
schools go back almost a half-century, and even in that short
period the freshman boys have shown a two-inch gain in average
height. Junoesque figures for the girls may mean good health,
but they occasion much social embarrassment, since few boys
like partners taller than themselves. The social problems of the
tall girl are real and in some places are being met by the for-
mation of clubs for tall people of both sexes, where everyone
is up on the same level.
The rapid gain in stature of recent times has brought other
amusing and troublesome problems. Mr. Pullman built his first
sleeping car in 1859 with a berth length of 71 inches from the
centre of one partition to the next, patterning his berths after
those in use on passenger ships of that day. In his next model
brought out 6 years later he increased this berth length to
72 inches. Continued complaints from travellers caused a further
increase to 75 inches, and finally to the present 77^-inch mat-
tress length in use on the sleeping cars recently put into service.
Cabin berths on ships caused their occupants similar cramped
inconvenience until the passenger liners changed over to full-
length regular beds. Plenty of ships still in service use the
old-style berths—far too narrow and short for the well-built
man of to-day. Seating space in theatres and other gathering
places also provides entirely too little knee and elbow room.
Building specifications simply have not kept pace with the
changing stature of the occupants.
Many of the really old beds now in existence are much too
short for their present owners. One of my friends, a well-built
man, bought a pair of beautiful antique beds for his seaside
cottage, but found that a 6-inch elongation of the sidc pieces
was necessary before they fitted his size. King Georgc of England,
in his pre-war visit to Paris, was given Napoleon’s bedchamber
and Napoleon’s own specially made bed for his use. Press
reports of the visit failed to mention just how he spent the night,
but Napoleon was 5 feet 2 inches in height and King George is
about 6 feet! Even the longest diagonal of the bed must still
have lacked several inches of providing sufficiënt room for him
to stretch out in tired relaxation.
The wife of a colleague on the university faculty loaned me
an old Crew List she had inherited from her New England
ancestors. In it were listed the heights and ages of men signing
on for a schooner voyage from Marblehead to Leghorn in
August of 1801. Most of the men were in their middle twenties
175
and their average height was 66 inches. New England young
men of to-day are about 4 inchejs taller than this. One member
of the crew was a 13-year-old cabin boy with a height of
56 inches, whereas both of my sons at 13 have been
66 inches! It is no wonder old-time sleeping berths were so
short—they were ample for the men using them in those days.
The average man is now about 70 inches tall in various regions
over the earth where recent human progress has been most
marked. Anthropologists say that this is about the height
attained by various other human groups back through the
centuries as they reached the pinnacle of their development.
The ancient Egyptians and Greeks, the Romans, the early
Indians of the American South-west, all achieved this stature
at the height of their glory and then declined in size as well
as in culture.
With the one long decline of historical times—the European
Dark Ages—man receded far from his former peak in both
culture and body size. The knights and nobles wearing the suits
of armour in those dark centuries would be mere pygmies com-
pared to the picked soldiers of to-day. Even a well-developed
American boy of 14 would have great difficulty getting into
most of the suits of armour now on exhibit in the world’s
museums. If the picked fighters of those days were small, fine-
boncd men, the common people must have been puny indeed.
And the damsels, who so often seemed in need of rescue by the
knights, were really fcmales in miniature who came to sexual
maturity about 3 years later than do our self-sufficient girls
of to-day. Back in ancient Greece, on the other hand, the
womcn were well developed and began their sexual cycles at
the same early age prevailing among the most advanced of
present-day girls.
European people of the Dark Ages seemed to be of low
vitality in every way. Small in body and late in developing, they
were also subject to pestilences which repeatedly lessened their
numbers. Poor transportation ^nd economie chaos greatly in-
creased their difficulties in securing proper food, leaving them
more susceptible to the disease scourges so prevalent through
those times. Leprosy, which to-day seems unable to make head-
way in middle temperate climates, swept up over the whole of
Europe in the severe form seen to-day only in regions o^tropical
heat. It and other scourges declined with the oncoming cold of
the Renaissance period, and European* populations began
a growth spurt which has since filled all the far corners of the
globe.
176
Since man has seemed Jo recede in body size and speed of
development with long historical periods of warmth and to
blossom forth in cooler centuries, it appears likely that people
of to-day should be .showing evidences of another beginning
decline in physique as earth temperatures again approach the
Dark Age level. The present long rise^in tcmperature has been
slow and halting except for the more severe upthrusts of the past
two decades, but the high temperatures of the last ten ycars
have carried us up close to the levels of Viking times, judging
by the depth of summer thaws in the old Greenland cemeteries.
If these temperature changes really are a factor in human
development, then the present astonishing growth tide should
by now be showing signs of a reversal.
Recent close check of college freshman stature indicates that
such reversal is indeed already in progress. Many months of the
most tedious and uninteresting kind of work were spent in
collecting and sorting data from some sixty-odd thousand
student health cards, lfut the point seemed of sufficiënt import-
ance to justify such efforts. Stature changes in entering freshmen
were studied at four state universities ranging in latitude from
North Carolina to Wisconsin. State schools were chosen because
their freshmen are mostly drawn from nearby areas and are
more representative of the population of their immediate
neighbourhood than would be the case with private or sectarian
schools.
Briefly stated, I found that the height of freshman girls at the
universities of North Carolina, Kentucky,, and Kansas became
stabilized about io years ago; The girls still seem to be getting
slightly heavier with each entering class, but no further height
increase is taking place. The height of boys stopped increasing
about 8 years ago, but they are still gaining in weight. Farthcr
north the Wisconsin freshmen still continue to gain in height
and weight, although the height gains are now quite small with
boys and girls of successive entering classes. Freshman boys in -
Wisconsin are on the average an inch taller and 5 pounds
heavier than those of Kansas and Kentucky.
-
During the recent decades of marked stature improvement
there had also been a change toward earlier onset of puberty.
Sexual cycles of freshman girls now begin a full year earlier than
they did 30 years ago. This trend toward ever earlier onset of
puberty has recently changed again, however, for North
Carolina freshman girls born since 1918 have shown a pro-
gressively later age for -beginning of their sexual cycles. At
Cincinnati and in Kansas the reversal came a year later, while
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in Wisconsin only the faintest hints of a turn have been found.
Even down in the high schools, body size is tending to become
stabilized for given age groups. The 15-year-old children of this
year’s class do not show so much gain over those of last year’s
as was the case a decade ago. In fact, following the severe heat
of the 1934 and 1936 summers in Cincinnati, the stature of
high-school children received an actual set-back. Instead of
showing the usual yearly improvement with successive classes
of 12-year-olds, for instance, children of this age were actually
smaller after those hot summers than had been the case in
former years.
Down at the grade-school ages stature is still improving. Èkch
year’s erop of 9-year-olds is better developed than was that of
the preceding year. But stabilization seems to be advancing
through the years of youth toward ever earlier ages, so that we
may expect before many years to see even the 5-year-olds of
one year no better than those of the year before.
Improved methods of feeding and a befter supply of fruits and
green vegetabfes at all seasons have no doubt been responsible
for much of the improvement in growth through childhood and
youth. This was probably an important factor also in the
advancing adult stature. But to-day we face an oncoming
stabilization and probable recession at a time when dietary
standards and the availability of proper foods are better than
ever before. Furthermore, the growth tide reversal is taking
place even in that part of the population usually best nourished.
Some force other than mere food deficiency must therefore be
at work over the earth, reversing our trend from racial
expansion in size and vitality into the start of a profound
rctreat.
This finding of a beginning biologie recession gives sharp
emphasis to the social and economie turmoil around us. Pon-
derous forces seem perhaps to be again tuming man’s course
downward after centuries of most remarkable advance and
achievement. If changes in world temperatures really affect us
in the ways pictured in these pages, then we do indeed seem
to be heading into a period of prolonged and disheartening
decline.
Perhaps you feel that this gloomy view of the situation is not
justified, that man’s control over his physical environment is
much better to-day than it was 2,óoo years ago, and that Science
will find ways to prevent the calamity which seems to impend.
Any such optimistic attitude seems hardly warranted, however,
for already there has been a sharp shrinkage of funds available
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for scientific research and higher education. European countries
suffered for years from this dwindling support while our funds
were still plentiful, but the financial trend of the last ten years
in America has cast dismay over those in charge of our in-
stitutions of leaming and research. Increasing aijiounts of
federal funds are being doled out from Washington in an effort
to keep scientists at their investigations, but with such support
often goes a degree of open or hidden dictation regarding the
kind of work to be done; any such reginientation of Science will
almost certainly result in impaired productivity.
Great discoveries usually arise from among a large number of
futile-appearing individual projects scattered here and there.
At first glance the multiplicity and duplication of these scattered
efforts make Science seem very wasteful, but no better way has
yet been found to give hidden genius its chance to emerge.
A very considerable element of chance lies behind the making
of important new discoveries, hence the broadest and least
restricted working base will always give greatest results.
Science of to-day should make every possible effort to put its
new findings into easily understood language, especially when-
ever they bear directly upon the public welfare. Many in-
vestigators have in the past scorned to recognize this duty; but
with the present increasing dependence upon public funds,
workers will be compelled to thus justify their projects in the
public eye. In passing from the field of abstract Science into
concrete utilitarianism, fundamental developments may suffer;
but it seems that the change is upon us. and that its implications
should be recognized by all. Here, as elsewhere, publicity can
easily be overdone and workers greatly handicapped by too
active salesmanship; but in general the reporting of scientific
findings is to-day very well done and merits the closest co-
operation from investigators.
In quite another direction there is also room for doubt as to
our ability to benefit long from present scientific knowledge.
To-day we see public and personal health measures producing
widespread reduction in many diseases and bringing about
a progressive lengthening of the life span. This has been off-
setting quite Iargely the reduction in birth rate of recent
decades. City water supplies have been purified with untold
saving of life. Malaria has been eradicated from large areas.
Cholera, typhus, and yellow fever are being restricted in thoir
spread from regions endemically affected. But eternal vigilance
is the price we must pay for these highly desirable results. And
vigilance is costly in energy terms.
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Tropical cities to-day maintain safe water and sewage Systems
only by an importation of energetic overseers from the more
dynamic temperate regions. If left entirely in local hands, they
would within a very few decades succumb to political graft and
revert to their former indolent filth. Even with smallpox vacci-
nation in the most enlightened regions, it is only constant
compulsion which maintains a high denree of mass immunity.
Were this compulsion removed, vaccination would soon drop
to quite ineffective levels, and real epidemics of the disease would
again appear. We have to-day a very good example of this in
the sector of the United States lying west and north of Missouri.
These 16 States provided almost nine-tenths of the country’s
15,111 smallpox cases in 1938, although they contain only
about a quarter of the total population. In 3 of them com-
pulsory vaccination is actually prohibited by law!
Even our food supply is made safe only by a thin veneer of
governmental control which is kept effective by constant vigil-
arice. Sickness and death lurk behind the least carelessness in
the preparation and handling of our milk supply, our canned
foods and meats, the drugs we use, and the beverages we drink.
And in the city air we breathe, only the faintest beginnings
have yet been made in the eradication of harmful contami-
nations.
A few decades of falling energy level and initiative could, and
probably would, bring aboiit a rapid crumbling of this fragile
defence shelter we have built up around our health and welfare.
Not only would scientific advance cease; We might well rapidly
slough off much of our present application of scientific dis-
coveries. Even in the mechanical field, or perhaps most markedly
there, regression would be disastrous. Mechanical developments
of to-day have become so complicated and involved, depending
on such high degree of accuracy and skill, that they would be
quickly affected by a loss of initiative and intense mental appli-
cation to the problems at hand. How long could air trans-
portation survive an increasing carelessness, when one mechanical
fault in construction or operation means certain death for many
passengers?
Our vaunted advances thus render us all the more vulnerable
to a recession in energy and initiative if it is to come. We need
not delude ourselves into a false sense of security behind our
present level of scientific development, for there is no such
security. What use was made of the valuable knowledge amassed
in early Greece and Rome when man descended into the murky
centuries of the Middle Ages? Yet medical knowledge of the
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early Greeks compared well with that of to-day except in the
phases dependent on mechanical skill and precision. In medicine
of to-day, as in transportation, industry, and the arts, we place
great reliance upon mechanical devices of highly technical
character. Should the control of society’s welfare be taken from
the intelligent and ingenious few and be grasped by the hands
of the ignorant many, our machine-age civilization would
speedily crumble and plunge us into another Dark Age.
As man has gone down in past tidal recessions, he not only
ceased actually adding to his knowledge but even lost his ability
to use that which he already possessed. For instance, it has been
recently pointed ’6ut that in early Egyptian and Babylonian
times mathematical knowledge was far advanced, but that from
about 2,000 to 500 b.c. no use whatever was made of such
functions as quadratic equations. With the early Greeks such
knowledge was revived and given much further progress. But
it once more suffered a complete eclipse during the Middle
Ages, as mankind receded in all other ways. Revival and
marked mathematical advances have again held sway since
the time of the Renaissance.
If such abstract and fundamental knowledge and mental
skill as that required for higher mathematical works can suffer
such complete eclipse with long periods of warmth and physical
decline, then we should no longer doubt the precariousness of
our present situation. Our complete dependence upon the
machine, and upon the intricate technical knowledge required
to keep it in operation, renders us very susceptible to the long
mental decline which now seems perhaps due to recur. Ours
will probably be looked back upon as the Mechanical Age of
Science and Industry, abandoned by man as he lost the mental
acuity to operate successfully the intricate devices previous
intelligence had invented.
Still another featurq of the tidal change which has been causing
concern in high places of several nations is the increasing reduc-
tion in reproductivity. For almost 80 years the fertility of
English women has been declining, and estimates have been
made that another 150 years of similar decline may bring the
population down to perhaps one-tenth of its present mass, with
reversion to a pastoral type of life. The wave of ninetcenth-
century reproductivity doubled human numbers on earth but
showed signs of slowing down by the end of the century; during
the early decades of the twentieth century this loss of momentum
became alarming in several of the previously most vigorous
peoples. Interesting speculation may well arise as to just how
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far this reduced fertility may go toward bringing about an
actual reduction in human numbers on earth during the
centuries ahead.
Serious social consequences arise from the change in racial
reproduction. Fewer children will soon mean less crowded
school conditions in the cities of America. For many decades we
have been frantically enlarging our school facilities, only to find
the ncw quarters soon just as crowded as the old. That will
soon cease and be replaced by a yearly decline in enrolment.
Such a decline has already begun, for in many American cities
primary-grade enrolment is 25-30 per cent. less than it was
ten years ago. A pre-war study in London showed that the
school population will be less than half what it is to-day if the
birth rate continues for another 20 years its course of the past
several decades. However, as the burden of educating fewer
children lessens through the decades, society will be faced with
the problem of caring for a growing proportion of aged de-
pendants. So perhaps we shall soon be converting our fine
school buildings into homes for the aged.
Man to-day faces a real challenge. He has the intelligence and
skill to control artificially those very factors of his environment
which produce wide fluctuations in racial capacity and develop-
ment. This intelligence, however, resides only in a few members
of the total human mass, and can function effectively only as
the masses understand, encourage, and apply its dictates.
Whether the genius and high intelligence of the few will be
permitted to function therefore depends entirely upon mass
psychology and the social and political motivating forces direct-
ing the course of events. If those forces favour individual
opportunity and the exercise of initiative, then mental genius
will be stimulated to the utmost. But with the mass demanding
“subsistence” and “social security,” less attention will be given
to encouraging the inventive genius of the race.
Many peoplc claim to see another dire threat to the usefulness
of Science in the labour revolution now taking place over the
wdrld. Rugged individualism of recent centuries had its faults
and selfish aspects, but its keen appreciation of the value of
scientific discoveries was largely responsible for the amazing
developments of the machine age in which we now live. But
may not labour develop a similar appreciatioh after it has had
more experience with the responsibilities of national guidance?
Here, as on the field of battle, Russia provides ground for
optimism, for her scientific men are given every encouragement
and occupy most favoured living conditions. A short 25 years
182
of labour rule there seems to have accomplished great things,
to have changed a lumbering, clumsy, discontented giant into
the fervently patriotic people who to-day are matching most
intricate skill in a war to the death against the world’s best
organizers and accomplished scientists. No matter how many
doubts we may have had regarding the Russian political
philosophy of recent decades, the whole world should now be
willing and anxious to understand more about the workings of
the forces which have wrought such changes.
There can be no gainsaying the fact that labour is definitely
on the move toward a higher place in world affairs. The labour-
union ferment had long been at work before the massive Russian
experiment began. The matter came to a head in Britain with
the general strike of 1926 and the formation of MacDonald’s
Labour Government. Even in far-off China, the Nationalist
uprising which reached Peking as we were leaving in 1928 was
largely on this basis; and the Chinese Red Army has given
a most able account of itself in the years of defcnce against
Japanese aggression. lts 6,000-mile trek around the Kuomintang
forces to get at the Japs in the north will live for ever among
the world legends of patriotic performances.
It is indeed unfortunate that the bitter struggle for power
here in America should have come at a time whcn long-
established trends of various kinds seemed to be charting a new
course. It looks very much as though our President was right
a few years ago when he said in effect that old landmarks no
longer sufficed, that we were putting out upon unchartcd seas
with only experimental soundings taken from time to time to
guide our course in the troubled years ahead. Events of
2,000 years ago, as ancient civilizations began slipping into the
abyss of the Dark Ages, can help us little to-day, for scenes and
people change with the passing millenniums. The rcal tragedy
of America—and other countries—of to-day is that ponderous
trends so often go on unrecognized, with a nat ion’s wealth and
accumulated advantages being dissipated in bitter class oppo-
sition. If only the certainty of the change and direction of trend
were more obvious and convincing, much human miscry and
wasting of valpes might be avoided.
If another recurring millennium of warmth is now really
plunging humanity back into a new Dark Age, we may well
consider the possible rearrangements in world power which
may take place. The present global conflict is erasing national
boundaries and bringing about new international alignments
which may have a profound inffuence upon the future course
183
of history. All now is fluidity, with every thinking person
realizing that there can be no return to pre-war conditions.
A new scheme of things must be constructed after the war has
ended. Who will sit at the head of the peace table and whose
will be the dominant voice?
Many people have professed to see a “rising tide of colour” as
the conquering grip of Western nations has shown signs of
relaxing its hold over the population masses of tropics and
Oriënt. The present onrush of Japanese conquest provides sharp
emphasis to the changed relations now clearly seen for the first
time. Japan has availed herself fully of the Western world’s
mechanical ingenuity to weid a powerful military machine.
Her men are no fighting prodigies, however, as has been
demonstrated whenever they have come to grips with American
forces under conditions of equal equipment. In fact, the ragged
troops of China, with almost no military background and
entirely negligible equipment, are often out-fighting the
Japanese invaders.
The really crucial factor responsible for Japanese conquests in
the Far East would seem to be a softening and crumbling of
the hold Western nations have long exercised there. The French
Empire is gone; that of Britain is rapidly following. The day of
a dominant white, race is past so far as the Oriënt and all Asia
are concerned, and the same may perhaps well hold for the
human masses throughout the tropics.
If and when Germany and Japan can be defeated and de-
militarized, it would seem logical that dominant places at the
peace table should be occupied by Russia and China. These are
the two peoples who have done the major part of the heavy
fighting, who have provided the most steadfast and grim resist-
ance to the aggressor nations, who ask nothing in return except
the privilege of pursuing their home affaire without outside
dictation. Endowed with a high degree of realism in world
affaire, they should have a large part in the post-war reconstruc-
tion of the Eurasian situation. They are the ones who must
continue to live alongside the present trouble-makers. People of
America are farther removed from the seat of trouble and have
a somewhat more academie interest in the whole matter. So
let Stalin take the head seat, with Chiang Kai-shek on his right
and the Anglo-Saxon group on his left.
As for a “rising tide of colour” engulfing the white race, the
chances for such are probably negligible so far as the Negro
race is concerned. Even though a diminution of climatic stimu-
lation should leave present temperate-zone nations at a lower
-
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energy level, they would still bc living on a higher plane than
would the tropical races. Negroes who migrate northward here
in America rapidly lose their high reproductivity, their birth
rate even falling below that of similar economie groups among
white residents.
The outlook is quite different, however, with respect to the
Mongoloid peoples. As the Western nations are subdued by
rising world temperatures and loss of cyclonic storminess, their
energy level will sink down nearer that of Japan and China.
The Oriental position will thus enjoy a relative improvement.
With the present rejuvenation China is enjoying from having
been pushed back into her more invigorating hinterland, she
may very well come forth as one of the world's great powers in
coming decades. Japan had her chance, but became too im-
patient of restraint and flew off into an orgy of conquest by
force. Let us hope and pray that realism, properly tinged with
altruism, will rule the course to be followed by the Big Three
groups at the peace table and in the decades to follow.
chapter 23
EPILOGUE
A person should free himself occasionally from
the humdrum details of daily life, focus his attention upon these
larger influences affecting his existence, and develop a better
appreciation of his own small place in the universe. The day’s
petty irritations and disappointments melt away into in-
significance as he merges his being into this celestial harmony
of mighty forces. The sim, moon, and beautiful planets travelling
along that much-used sky pathway all have their part in human
affairs. When viewed against the background of this outside
control, the doings of one’s neighbours or attempts to amass
earthly wealth lose much of their seeming importance. Great
consolation comes with the knowledge that other forces than
man’s own puny efforts are at work determining his fate.
My moments of keenest satisfaction and most complete
mental peace have been those when the grandeur of nature’s
artistry has cast its spell over me. Such was the case as I stood
on the Peking Wall—high above the teeming masses of China—
to view the gorgeous sunset colouring over the Western Hills;
also as I gazed across Lake Geneva from the pension balcony
185
to watch Mount Blanc catch the final rays of the setting sun;
and as I sought a secluded spot on the ship’s deck in mid-
Pacific with almost the regularity of a sun worshipper to enjoy
the glories of sunrise and sunset across placid tropical waters.
Even as a child I wondered what influences were behind the
grandeur and beauty so often displayed in sky colouring. Now,
as an adult with some knowledge of what it all means, I can
sense in these physical forces the near presence of the real
Ruler of Creation.
Humble acknowledgment of one’s dependence upon these
directing cosmic influences can well replace much of the ego-
centric bigotry recent generations of people have developed.
In certain favoured climates of the earth man has indeed per-
formed great feats, especially through the stimulating cold of
the past few centuries; but with all his remarkable advances,
he should keep before him a ciear realization of the environ-
mental factors which have made his achievements possible—
and which may some day change him into a somewhat less
superior being. Humility is said to be good for the soul, and
here lies abundant cause for human humbleness. The energetic
man of stimulating regions should appreciate the good fortune
which placed him under such favourable circumstances. He
has no cause for egotism; instead he should give credit to the
natural forces which made possible his accomplishments,
remembering that climate makes the man.
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