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THE NEW AIR WORLD
[Illustration: FIG. 4.—INSTRUMENT SHELTER. Frontispiece.
(_Page 66_)]
THE
NEW AIR WORLD
_The Science of Meteorology
Simplified_
BY
WILLIS LUTHER MOORE, SC.D., LL.D.
PROFESSOR METEOROLOGY GEORGE WASHINGTON
UNIVERSITY, EIGHTEEN YEARS CHIEF
UNITED STATES WEATHER BUREAU
[Illustration: (colophon)]
BOSTON
LITTLE, BROWN, AND COMPANY
1922
_Copyright, 1922_,
BY LITTLE, BROWN, AND COMPANY.
_All rights reserved_
Published October, 1922
PRINTED IN THE UNITED STATES OF AMERICA
AFFECTIONATELY DEDICATED
TO
A FRIEND OF MANY AND PLEASANT YEARS
A BELOVED TEACHER AND A
GREAT CHEMIST
DR. CHARLES E. MUNROE, PH.D.
INTRODUCTION
The author’s “Descriptive Meteorology” (Appleton, 1914) is designed
for the teaching of those who intend to make Meteorology a
profession. This book is planned for the reading of those who desire
to know something of the wonders of the New Air World into which man
is just now entering, for those who desire to become weatherwise and
make forecasts for themselves, and to apply their knowledge to their
business, their health, and their happiness; and for the reading of
the more advanced pupils of the public schools.
So far as possible technical terms are avoided and an effort made to
tell a simple story that will awaken curiosity and lead the reader
to wish to know more and more of the mysteries of the atmosphere, of
which practically nothing was known at the time of the landing of
the Pilgrims, Torricelli not having discovered the barometer until
twenty-three years later. It will be made plain how atmospheric
air was formed, how long it will remain, whither it will go, how it
is heated, cooled, and lighted; where and how storms, cold waves,
clouds, frosts, and fair-weather conditions originate and how move;
how the cyclone, the tornado, and the thunderstorm may be recognized
on the Daily Weather Map of the Government and their future
activities forecast; how a fund of simple yet wonderful information
that will be of inestimable value may be acquired by any intelligent
person.
The author acknowledges courtesies extended to him by Prof. Charles
F. Marvin, present chief of the Weather Bureau, and by R. H.
Weightman, chief clerk of the Bureau, in the matter of securing
several important illustrations; and like favors extended to him by
D. Appleton and Company, John Wiley & Sons, and the Taylor Instrument
Company, of Rochester, N. Y.
W. L. M.
AUGUST, 1922
CONTENTS
CHAPTER PAGE
INTRODUCTION vii
I ATMOSPHERES OF THE EARTH, THE SUN, AND THE PLANETS 1
II A SYNOPTIC PICTURE OF THE AIR 7
III EXPLORATIONS OF THE ATMOSPHERE 18
IV EARTH’S FOUR ATMOSPHERES 29
V LIGHT, HEAT, AND TEMPERATURE 48
VI THE ADVANTAGE OF TAKING WEATHER OBSERVATIONS AND
APPLYING THEM TO ONE’S PERSONAL NEEDS 64
VII FROST 85
VIII WIND AND PRESSURE OF THE GLOBE 98
IX HOW TO FORECAST FROM THE DAILY WEATHER MAP 112
X CLIMATE 161
XI HOW CLIMATE IS MODIFIED AND CONTROLLED 188
XII CIVILIZATION FOLLOWS THE STORM TRACKS 213
XIII HAS OUR CLIMATE CHANGED? 225
XIV CLIMATES FOR HEALTH AND PLEASURE 245
XV CONDENSATION 282
XVI DEVELOPMENT OF THE AMERICAN WEATHER SERVICE 291
INDEX 307
LIST OF FIGURES
Instrument Shelter (Figure 4) _Frontispiece_
FIGURE PAGE
1. Winter and Summer Vertical Temperature Gradients, in
degrees Centigrade and Fahrenheit 12
2. Showing light from lamp a passing into dust-free air
at _b_, and passing out at _c_ without illuminating
the interior 46
3. Standard Weather Bureau Kite 64
5. Comparison of the Thermometer Scales 67
6. Dry and Wet Bulb Thermometers 68
7. Mercurial Barometer 78
8. Continuous records of the temperature from 4 P.M.
to 9 A.M. 87
9. Continuous records of the temperature 5 feet and 35
feet above ground on a tower in a pear orchard 95
10. Average dates of last killing frost in Spring 96
11. Average dates of first killing frost in Fall 97
12. Trade wind circulation 99
13. Average surface winds and pressure of the globe 102
14. How winds would blow into a cyclone on a non-rotating
earth 108
15. Deflection of wind due to earth’s rotation 109
16. Annual, summer, and winter wind velocities with
altitude 110
17. Tornado Cloud 145
18. The St. Louis Tornado of May 27, 1896, Shot a Pine
Scantling through the Iron Side of the Eads Bridge 147
19. The St. Louis Tornado of May 27, 1896, Shot a Shovel
Six Inches into the Body of a Tree 147
20. The St. Louis Tornado Drove Straws One half Inch
into Wood 149
21. Equinoxes, March 21 and September 22 163
22. Summer Solstice, June 21 164
23. Winter Solstice, December 21 164
24. Winter and Summer Solstices, and the Equinoxes 165
25. As angle of incidence decreases from 90° to 10° the
heat received on upper end of blocks is spread
over greater area at bottom, and its temperature
diminished 165
26. Altitude attained by Sun at midday and length of its
track above the horizon at the Summer and Winter
Solstices and at the two Equinoxes 167
27. Summer day and Summer night temperatures in the same
narrow valley 204
28. Average Monthly Temperature and Rainfall of Typical
Places in North America 207
29. Average Monthly Temperature and Rainfall of Typical
Places in the Old World 208
30. Changes in Climate in California during the Christian
Era 237
31. Snow Crystals 286
LIST OF CHARTS
CHART PAGE
1. High and Low Centers of Action and Prevailing Winds
of the Globe for July 99
2. High and Low Centers of Action and Prevailing Winds
of the Globe for January 100
3. Winter Storm, December 15, 1893, 8 A.M. 114
4. Winter Storm, December 15, 1893, 8 P.M. 116
5. Winter Storm, December 16, 1893, 8 A.M. 118
6. Cold Wave Zones, March to November. Amount of Fall
and Verifying Limit 127
7. Cold Wave Zones, December, January, and February.
Amount of Fall and Verifying Limit 128
8. Lowest Temperatures in the United States, 1871-1913 129
9. Number of Cold Waves, 1904-1914, Inclusive 130
10. Storm Tracks for August for Ten Years 132
11. Storm Tracks for February for Ten Years 134
12. Average Maximum Temperature for July 195
13. Ocean Currents 196
14. Mean Annual Isotherms 200
15. Normal Wind Direction and Velocity for January and
February 202
16. Normal Wind Direction and Velocity for July and
August 204
17. Map of Climatic Energy 221
18. Density of Population in the United States, 1910 222
THE NEW AIR WORLD
CHAPTER I
ATMOSPHERES OF THE EARTH, THE SUN, AND THE PLANETS
=How Atmospheres Are Formed.= Once there were no such things on the
earth as hills and mountains, singing brooks, roaring rivers and vast
oceans; and the delicately hued landscape, with its winding roads,
hedges, flowers, green fields, and golden grain, had not evolved from
the atmosphere. The earth had not yet cooled down to the condition of
a solid crust, everything that the eye now sees existed in the form
of invisible gases, or as clouds incandescent with white heat. Fiery
blasts swirled over the face of the earth. Storms a million times
more powerful than the most destructive West Indian hurricane of the
present day moved through the indescribably hot atmosphere, throwing
down not rain as we understand it, but liquid earth and metal, as
their rising clouds ascended and cooled. It is difficult for the
human mind to grasp the wonders of this.
Small planets cool quicker than large ones and sooner come to
the conditions of a crust and to a temperature suitable for the
development of the various forms of life.
=Atmosphere of the Sun.= To the unaided eye it appears as a smooth,
bright, quiescent sphere, but the telescope reveals millions of
agitations and hundreds of red flames that shoot outward to distances
of hundreds of thousands of miles. One can form no adequate picture
of the convulsions of the atmosphere of the sun. During eclipses,
when the intense glare of its center is obscured, hydrogen flames may
be seen darting outward for as much as a million miles.
=Lifeless Planets.= The larger a planet the longer is the time that
must elapse before the hot vapors of rock and metal, which largely
compose its early atmosphere, cool and congeal into a crust, leaving
as a residual an atmosphere of such heat, density, and composition as
to permit of the beginnings of the forms of life that have inhabited
the world. Before the sun can reach this condition, an indescribable
period will have elapsed, its light will have gone out, its heat
will have ceased to reach the earth and the other planets in
quantities sufficient to maintain life, the earth will have been dead
millions of years, and the sun itself will only receive heat and
light from the feeble rays of the stars that, unlike itself, have not
yet ceased to shine. But even then the sun ever must remain dead, for
there is no external source whence it may receive heat. No vegetation
can adorn it, no water flow upon its surface, neither can the foot of
any man press its soil.
Jupiter, and perhaps Neptune, Uranus, and Saturn, have hot
atmospheres still in violent agitation,—molten surfaces composed
of all kinds of matter, from which bubble and boil off hot clouds
of vapor that surge about in huge eddies or cyclonic storms, and
that here and there are shot outward in tongues of fire. The earth
millions of years ago had a similar atmosphere. But when the heat
energy of these vaporous planets wanes, and they cool down, as the
earth did many years ago, the simplest forms of life cannot be
evolved upon them, for they are too far away from the sun to receive
life-giving heat. Mars receives less than half the intensity of the
solar rays that come to the earth, Jupiter only 0.037, Saturn 0.011,
Uranus 0.003, and Neptune 0.001.
In due time—some hundreds of millions of years—the cooling of the
sun will leave the earth to freeze and all life to become extinct,
unless, perchance, the oxygen of the air is so far absorbed by its
rocks, or filtered away into space, as to destroy life before that
time. No matter what may be the achievements of the human mind, what
wonderful civilizations may be developed, what powerful empires
created, or what wonderful secrets of creation discovered, it seems
certain that these all will pass away, and finally the surface of
the earth be as if man never lived. The dust of ages will wipe out
and obliterate every trace and vestige of the operations of life.
Silence, cold, and darkness will then reign supreme. But the time of
this is indescribably far off in the future, and man will have ample
opportunity to develop to the highest mental and spiritual estates of
which he has inherent possibilities.
The moon already is dead. If it is formed of matter abandoned by the
earth, as we believe, it once must have had an atmosphere, a portion
of which was absorbed by its rocks as it cooled, and the remainder
lost as the result of the low power of attraction of so small a
body, which is insufficient to prevent the darting molecules of the
gases of its air from shooting off into space. The absence of an
atmospheric covering allows the heat from the sun to escape almost
as rapidly as it is received; and the long nights of the moon (each
as long as fourteen of our days) during which the sun’s rays are
entirely cut off, permit the temperature of the dark side to fall to
something like -400° F.
=How Atmospheres Are Maintained and How Lost.= The processes of
nature are always adding to the various gases of the atmosphere in
some ways, and transforming or taking from them in other ways. On the
earth the loss and the gain are so nearly equal as to maintain at
present a nearly constant condition. Marked changes have taken place,
however, in long geologic periods. Our early atmosphere probably
contained large quantities of carbon dioxide which were absorbed by
the rank vegetable growth that now forms the coal beds of the earth,
and the slowly cooling rocks that constitute the crust took in large
quantities of oxygen; in fact, nearly one half of the weight of the
crust of the earth is composed of the latter element.
In consequence it may be said that our present atmosphere is what
remained after the earth had absorbed its gases nearly to depletion,
and after the lighter gases, like hydrogen and helium, which seem to
have too great molecular velocity to be imprisoned by the earth’s
attraction of gravitation, had been lost in space. Gases that cannot
be held by the moon may be imprisoned by the earth and those that can
escape from the earth may be held by the larger planets.
=Height of the Earth’s Atmosphere.= Exact computation has shown that
if the air were the same density at all elevations, which it is not,
it would extend upward a distance of only five miles. From laws that
are well understood it is known that at a height of thirty miles
the atmosphere is only about one hundredth as dense as it is at the
surface of the earth, and that at fifty miles it is too light to
manifest a measurable pressure. The oxygen ceases at about thirty
miles and the nitrogen at about fifty miles, the water vapor being
restricted below the five-mile level. The appearance of meteors,
which are rendered luminous by rushing into the earth’s atmosphere,
and whose altitudes have been determined by simultaneous observations
at several stations, reveals the presence of hydrogen and helium at a
height of nearly two hundred miles.