rigidity. It is a matter of common observation that rocks stand high in
this respect and in the consequent difficulty with which they can be
bent without breaking. Because of the earth's contraction the crust
endures a constant strain, which must gradually become enormous. This
strain is increased by the fact that sediment is transferred from the
lands to the borders of the sea and there forms areas of thick
accumulation. From this has arisen the doctrine of isostasy, or of the
equalization of crustal pressure. An important illustration of this is
the oceanward and equatorial creep which has been described in Chapter
XI. There we saw that when the lands have once been raised to high
levels or when a shortening of the earth's axis by contraction has
increased the oceanic bulge at the equator, or when the reverse has
happened because of tidal retardation, the outer part of the earth
appears to creep slowly back toward a position of perfect isostatic
adjustment. If the sun had no influence upon the earth, either direct or
indirect, isostasy and other terrestrial processes might flex the
earth's crust so gradually that changes in the form and height of the
lands would always take place slowly, even from the geological point of
view. Thus erosion would usually be able to remove the rocks as rapidly
as they were domed above the general level. If this happened, mountains
would be rare or unknown, and hence climatic contrasts would be far less
marked than is actually the case on our earth where crustal movements
have repeatedly been rapid enough to produce mountains.
Nature's methods rarely allow so gradual an adjustment to the forces of
isostasy. While the crust is under a strain, not only because of
contraction, but because of changes in its load through the transference
of sediments and the slow increase or decrease in the bulge at the
equator, the atmosphere more or less persistently carries on the tapping
process. The violence of that process varies greatly, and the variations
depend largely on the severity of the climatic contrasts. If the main
outlines of the cyclonic hypothesis are reliable, one of the first
effects of a disturbance of the sun's atmosphere is increased storminess
upon the earth. This is accompanied by increased intensity in almost
every meteorological process. The most important effect, however, so far
as the earth's crust is concerned would apparently be the rapid and
intense changes of atmospheric pressure which would arise from the swift
passage of one severe storm after another. Each storm would be a little
tap on the tensely strained crust. Any single tap might be of little
consequence, even though it involved a change of a billion tons in the
pressure on an area no larger than the state of Rhode Island. Yet a
rapid and irregular succession of such taps might possibly cause the
crust to crack, and finally to collapse in response to stresses arising
from the shrinkage of the earth.
Another and perhaps more important effect of variations in storminess
and especially in the location of the stormy areas would be an
acceleration of erosion in some places and a retardation elsewhere. A
great increase in rainfall may almost denude the slopes of soil, while a
diminution to the point where much of the vegetation dies off has a
similar effect. If such changes should take place rapidly, great
thicknesses of sediment might be concentrated in certain areas in a
short time, thus disturbing the isostatic adjustment of the earth's
crust. This might set up a state of strain which would ultimately have
to be relieved, thus perhaps initiating profound crustal movements.
Changes in the load of the earth's crust due to erosion and the
deposition of sediment, no matter how rapid they may be from the
geological standpoint, are slow compared with those due to changes in
barometric pressure. A drop of an inch in barometric pressure is
equivalent to the removal of about five inches of solid rock. Even under
the most favorable circumstances, the removal of an average depth of
five inches of rock or its equivalent in soil over millions of square
miles would probably take several hundred years, while the removal of a
similar load of air might occur in half a day or even a few hours. Thus
the erosion and deposition due to climatic variations presumably play
their part in crustal deformation chiefly by producing crustal stresses,
while the storms, as it were, strike sharp, sudden blows.
Suppose now that a prolonged period of world-wide mild climate, such as
is described in Chapter X, should permit an enormous accumulation of
stresses due to contraction and tidal retardation. Suppose that then a
sudden change of climate should produce a rapid shifting of the deep
soil that had accumulated on the lands, with a corresponding
localization and increase in strains. Suppose also that frequent and
severe storms play their part, whether great or small, by producing an
intensive tapping of the crust. In such a case the ultimate collapse
would be correspondingly great, as would be evident in the succeeding
geological epoch. The sea floor might sink lower, the continents might
be elevated, and mountain ranges might be shoved up along lines of
special weakness. This is the story of the geological period as known to
historical geology. The force that causes such movements would be the
pull of gravity upon the crust surrounding the earth's shrinking
interior. Nevertheless climatic changes might occasionally set the date
when the gravitative pull would finally overcome inertia, and thus usher
in the crustal movements that close old geologic periods and inaugurate
new ones. This, however, could occur only if the crust were under
sufficient strain. As Lawson[139] says in his discussion of the "elastic
rebound theory," the sudden shifts of the crust which seem to be the
underlying cause of earthquakes "can occur only after the accumulation
of strain to a limit and ... this accumulation involves a slow creep of
the region affected. In the long periods between great earthquakes the
energy necessary for such shocks is being stored up in the rocks as
elastic compression."
If a period of intense storminess should occur when the earth as a whole
was in such a state of strain, the sudden release of the strains might
lead to terrestrial changes which would alter the climate still further,
making it more extreme, and perhaps permitting the storminess due to the
solar disturbances to bring about glaciation. At the same time if
volcanic activity should increase it would add its quota to the tendency
toward glaciation. Nevertheless, it might easily happen that a very
considerable amount of crustal movement would take place without causing
a continental ice sheet or even a marked alpine ice sheet. Or again, if
the strains in the earth's crust had already been largely released
through other agencies before the stormy period began, the climate might
become severe enough to cause glaciation in high latitudes without
leading to any very marked movements of the earth's crust, as apparently
happened in the Mid-Silurian period.
FOOTNOTES:
[Footnote 125: E. Kirk: Paleozoic Glaciation in Alaska; Am. Jour. Sci.,
1918, p. 511.]
[Footnote 126: J. Milne: Catalogue of Destructive Earthquakes; Rep.
Brit. Asso. Adv. Sci., 1911.]
[Footnote 127: Wm. Bowie: Lecture before the Geological Club of Yale
University. See Am. Jour. Sci., 1921.]
[Footnote 128: Chas. Davisson: On the Annual and Semi-annual Seismic
Periods; Roy. Soc. of London, Philosophical Transactions, Vol. 184,
1893, 1107 _ff._]
[Footnote 129: C. G. Knott: The Physics of Earthquake Phenomena, Oxford,
1908.]
[Footnote 130: In Table 8 the first column indicates the region; the
second, the dates; and the third, the number of shocks. The fourth
column gives the month in which the annual maximum occurs when the crude
figures are smoothed by the use of overlapping six-monthly means. In
other words, the average for each successive six months has been placed
in the middle of the period. Thus the average of January to June,
inclusive, is placed between March and April, that for February to July
between April and May, and so on. This method eliminates the minor
fluctuations and also all periodicities having a duration of less than a
year. If there were no annual periodicity the smoothing would result in
practically the same figure for each month. The column marked
"Amplitude" gives the range from the highest month to the lowest divided
by the number of earthquakes and then corrected according to Schuster's
method which is well known to mathematicians, but which is so confusing
to the layman that it will not be described. Next, in the column marked
"Expected Amplitude," we have the amplitude that would be expected if a
series of numbers corresponding to the earthquake numbers and having a
similar range were arranged in accidental order throughout the year.
This also is calculated by Schuster's method in which the expected
amplitude is equal to the square root of "pi" divided by the number of
shocks. When the actual amplitude is four or more times the expected
amplitude, the probability that there is a real periodicity in the
observed phenomena becomes so great that we may regard it as practically
certain. If there is no periodicity the two are equal. The last column
gives the number of times by which the actual exceeds the expected
amplitude, and thus is a measure of the probability that earthquakes
vary systematically in a period of a year.]
[Footnote 131: N. F. Drake: Destructive Earthquakes in China; Bull.
Seism. Soc. Am., Vol. 2, 1912, pp. 40-91, 124-133.]
[Footnote 132: The only other explanation that seems to have any
standing is the psychological hypothesis of Montessus de Ballore as
given in Les Tremblements de Terre. He attributes the apparent seasonal
variation in earthquakes to the fact that in winter people are within
doors, and hence notice movements of the earth much more than in summer
when they are out of doors. There is a similar difference between
people's habits in high latitudes and low. Undoubtedly this does have a
marked effect upon the degree to which minor earthquake shocks are
noticed. Nevertheless, de Ballore's contention, as well as any other
psychological explanation, is completely upset by two facts: First,
instrumental records show the same seasonal distribution as do records
based on direct observation, and instruments certainly are not
influenced by the seasons. Second, in some places, notably China, as
Drake has shown, the summer rather than the winter is very decidedly the
time when earthquakes are most frequent.]
[Footnote 133: A comparison of tropical hurricanes with earthquakes is
interesting. Taking all the hurricanes recorded in August, September,
and October, from 1880 to 1899, and the corresponding earthquakes in
Milne's catalogue, the correlation coefficient between hurricanes and
earthquakes is +0.236, with a probable error of +-0.082, the month being
used as the unit. This is not a large correlation, yet when it is
remembered that the hurricanes represent only a small part of the
atmospheric disturbances in any given month, it suggests that with
fuller data the correlation might be large.]
[Footnote 134: Ellsworth Huntington: The Geographic Work of Dr. M. A.
Veeder; Geog. Rev., Vol. 3, March and April, 1917, Nos. 3 and 4.]
[Footnote 135: Frank Schlesinger: Variations of Latitude; Their Bearing
upon Our Knowledge of the Interior of the Earth; Proc. Am. Phil. Soc.,
Vol. 54, 1915, pp. 351-358. Also Smithsonian Report for 1916, pp.
248-254.]
[Footnote 136: Harold Jeffreys: Causes Contributory to the Annual
Variations of Latitude; Monthly Notices, Royal Astronomical Soc., Vol.
76, 1916, pp. 499-525.]
[Footnote 137: John Milne: British Association Reports for 1903 and
1906.]
[Footnote 138: C. G. Knott: The Physics of Earthquake Phenomena, Oxford,
1908.]
[Footnote 139: A. C. Lawson: The Mobility of the Coast Ranges of
California; Univ. of Calif. Pub., Geology, Vol. 12, No. 7, pp. 431-473.]
CONCLUSION
Here we must bring this study of the earth's evolution to a close. Its
fundamental principle has been that the present, if rightly understood,
affords a full key to the past. With this as a guide we have touched on
many hypotheses, some essential and some unessential to the general line
of thought. The first main hypothesis is that the earth's present
climatic variations are correlated with changes in the solar atmosphere.
This is the keynote of the whole book. It is so well established,
however, that it ranks as a theory rather than as an hypothesis. Next
comes the hypothesis that variations in the solar atmosphere influence
the earth's climate chiefly by causing variations not only in
temperature but also in atmospheric pressure and thus in storminess,
wind, and rainfall. This, too, is one of the essential foundations on
which the rest of the book is built, but though this cyclonic hypothesis
is still a matter of discussion, it seems to be based on strong
evidence. These two hypotheses might lead us astray were they not
balanced by another. This other is that many climatic conditions are due
to purely terrestrial causes, such as the form and altitude of the
lands, the degree to which the continents are united, the movement of
ocean currents, the activity of volcanoes, and the composition of the
atmosphere and the ocean. Only by combining the solar and the
terrestrial can the truth be perceived. Finally, the last main
hypothesis of this book holds that if the climatic conditions which now
prevail at times of solar activity were magnified sufficiently and if
they occurred in conjunction with certain important terrestrial
conditions of which there is good evidence, they would produce most of
the notable phenomena of glacial periods. For example, they would
explain such puzzling conditions as the localization and periodicity of
glaciation, the formation of loess, and the occurrence of glaciation in
low latitudes during Permian and Proterozoic times. The converse of this
is that if the conditions which now prevail at times when the sun is
relatively inactive should be intensified, that is, if the sun's
atmosphere should become calmer than now, and if the proper terrestrial
conditions of topographic form and atmospheric composition should
prevail, there would arise the mild climatic conditions which appear to
have prevailed during the greater part of geological time. In short,
there seems thus far to be no phase of the climate of the past which is
not in harmony with an hypothesis which combines into a single unit the
three main hypotheses of this book, solar, cyclonic, and terrestrial.
Outside the main line of thought lie several other hypotheses. Several
of these, as well as some of the main hypotheses, are discussed chiefly
in _Earth and Sun_, but as they are given a practical application in
this book they deserve a place in this final summary. Each of these
secondary hypotheses is in its way important. Yet any or all may prove
untrue without altering our main conclusions. This point cannot be too
strongly emphasized, for there is always danger that differences of
opinion as to minor hypotheses and even as to details may divert
attention from the main point. Among the non-essential hypotheses is the
idea that the sun's atmosphere influences that of the earth electrically
as well as thermally. This idea is still so new that it has only just
entered the stage of active discussion, and naturally the weight of
opinion is against it. Although not necessary to the main purpose of
this book, it plays a minor role in the chapter dealing with the
relation of the sun to other astronomical bodies. It also has a vital
bearing on the further advance of the science of meteorology and the art
of weather forecasting. Another secondary hypothesis holds that sunspots
are set in motion by the planets. Whether the effect is gravitational or
more probably electrical, or perhaps of some other sort, does not
concern us at present, although the weight of evidence seems to point
toward electronic emissions. This question, like that of the relative
parts played by heat and electricity in terrestrial climatic changes,
can be set aside for the moment. What does concern us is a third
hypothesis, namely, that if the planets really determine the periodicity
of sunspots, even though not supplying the energy, the sun in its flight
through space must have been repeatedly and more strongly influenced in
the same way by many other heavenly bodies. In that case, climatic
changes like those of the present, but sometimes greatly magnified, have
presumably arisen because of the constantly changing position of the
solar system in respect to other parts of the universe. Finally, the
fourth of our secondary hypotheses postulates that at present the date
of movements of the earth's crust is often determined by the fact that
storms and other meteorological conditions keep changing the load upon
first one part of the earth's surface and then upon another. Thus
stresses that have accumulated in the earth's isostatic shell during the
preceding months are released. In somewhat the same way epochs of
extreme storminess and rapid erosion in the past may possibly have set
the date for great movements of the earth's crust. This hypothesis, like
the other three in our secondary or non-essential group, is still so new
that only the first steps have been taken in testing it. Yet it seems to
deserve careful study.
In testing all the hypotheses here discussed, primary and secondary
alike, the first necessity is a far greater amount of quantitative work.
In this book there has been a constant attempt to subject every
hypothesis to the test of statistical facts of observation.
Nevertheless, we have been breaking so much new ground that in many
cases exact facts are not yet available, while in others they can be
properly investigated only by specialists in physics, astronomy, or
mathematics. In most cases the next great step is to ascertain whether
the forces here called upon are actually great enough to produce the
observed results. Even though they act only as a means of releasing the
far greater forces due to the contraction of the earth and the sun, they
need to be rigidly tested as to their ability to play even this minor
role. Still another line of study that cries aloud for research is a
fuller comparison between earthquakes on the one hand and meteorological
conditions and the wandering of the poles on the other. Finally, an
extremely interesting and hopeful quest is the determination of the
positions and movements of additional stars and other celestial bodies,
the faint and invisible as well as the bright, in order to ascertain the
probable magnitude of their influence upon the sun and thus upon the
earth at various times in the past and in the future. Perhaps we are
even now approaching some star that will some day give rise to a period
of climatic stress like that of the fourteenth century, or possibly to a
glacial epoch. Or perhaps the variations in others of the nearer stars
as well as Alpha Centauri may show a close relation to changes in the
sun.
Throughout this volume we have endeavored to discover new truth
concerning the physical environment that has molded the evolution of all
life. We have seen how delicate is the balance among the forces of
nature, even though they be of the most stupendous magnitude. We have
seen that a disturbance of this balance in one of the heavenly bodies
may lead to profound changes in another far away. Yet during the billion
years, more or less, of which we have knowledge, there appears never to
have been a complete cataclysm involving the destruction of all life.
One star after another, if our hypothesis is correct, has approached the
solar system closely enough to set the atmosphere of the sun in such
commotion that great changes of climate have occurred upon the earth.
Yet never has the solar system passed so close to any other body or
changed in any other way sufficiently to blot out all living things. The
effect of climatic changes has always been to alter the environment and
therefore to destroy part of the life of a given time, but with this
there has invariably gone a stimulus to other organic types. New
adaptations have occurred, new lines of evolutionary progress have been
initiated, and the net result has been greater organic diversity and
richness. Temporarily a great change of climate may seem to retard
evolution, but only for a moment as the geologist counts time. Then it
becomes evident that the march of progress has actually been more rapid
than usual. Thus the main periods of climatic stress are the most
conspicuous milestones upon the upward path toward more varied
adaptation. The end of each such period of stress has found the life of
the world nearer to the high mentality which reaches out to the utmost
limits of space, of time, and of thought in the search for some
explanation of the meaning of the universe. Each approach of the sun to
other bodies, if such be the cause of the major climatic changes, has
brought the organic world one step nearer to the solution of the
greatest of all problems,--the problem of whether there is a psychic
goal beyond the mental goal toward which we are moving with ever
accelerating speed. Throughout the vast eons of geological time the
adjustment of force to force, of one body of matter to another, and of
the physical environment to the organic response has been so delicate,
and has tended so steadily toward the one main line of mental progress
that there seems to be a purpose in it all. If the cosmic uniformity of
climate continues to prevail and if the uniformity is varied by changes
as stimulating as those of the past, the imagination can scarcely
picture the wonders of the future. In the course of millions or even
billions of years the development of mind, and perhaps of soul, may
excel that of today as far as the highest known type of mentality excels
the primitive plasma from which all life appears to have arisen.
INDEX
* Indicates illustrations.
Abbot, C. G., cited, 45, 52, 237, 238, 239.
Aboskun, 104.
Africa, earthquakes, 301;
East, _see_ East Africa;
lakes, 143;
North, _see_ North Africa.
African glaciation, 266.
Air, _see_ Atmosphere.
Alaska, glacial till in, 287;
Ice Age in, 221.
Albrecht, cited, 304.
Alexander, march of, 88 f.
Allard, H. A., cited, 183, 184.
Alpha Centauri, companion of, 280;
distance from sun, 262;
luminosity, 278;
speed of, 281;
variations, 282.
Alps, loess in, 159;
precipitation in, 141;
snow level in, 139.
Altair, companion of, 280;
luminosity, 278;
speed of, 281.
Amazon forest, temperature, 17.
Ancylus lake, 217.
Andes, snow line, 139.
Animals, climate and, 1.
Antarctica, mild climate, 219;
thickness of ice in, 125;
winds, 135, 161.
Anti-cyclonic hypothesis, 135 ff.
Appalachians, effect on ice sheet, 121.
Arabia, civilization in, 67.
Aral, Sea of, 108.
Archean rocks, 211.
Archeozoic, 3 f.;
climate of, 267.
Arctic Ocean, submergence, 219.
Arctowski, H., cited, 29, 46, 244.
Argon, increase of, 236.
Arizona, rainfall, 89, 108;
trees measured in, 73.
Arrhenius, S., cited, 36, 254.
Arsis, of pulsation, 24.
Asbjoern Selsbane, corn of, 101.
Asia, atmospheric pressure, 298;
central, changes of climate, *75;
central, post-glacial climate, 271;
climate, 66;
glaciation in, 131;
storminess in, 60;
western, climate in, 84 f.
Atlantic Ocean, storminess, 57.
Atmosphere, changes, 19 f., 229;
composition of, 223-241;
effect on temperature, 231.
Atmospheric circulation, glaciation and, 42.
Atmospheric electricity, solar relations of, 56.
Atmospheric pressure, earthquakes and, 298;
evaporation and, 237;
increase in, 239;
redistribution of, 49;
variation, 53.
Australia, East, mild climate, 219;
precipitation, 144.
Axis, earth's, 48;
wabbling of, 301.
Bacon, Sir Francis, cited, 27.
Bacubirito, meteor at, 246.
Baltic Sea, as lake, 217;
freezing of, 100;
ice, 26;
storm-floods, 99;
submergence, 219.
Bardsson, Ivar, 106.
Barkow, cited, 135.
Barometric pressure, solar relations of, 56.
Barrell, J., cited, 3, 200, 213, 234.
Bartoli, A. G., cited, 257.
Bauer, L. A., cited, 150.
Beaches, under water, 97.
Beadnell, H. J. L., cited, 143.
Beluchistan, rainfall, 89.
Bengal, Bay of, cyclones in, 149.
Bengal, famine in, 104 f.
Berlin, rainfall and temperature, 93.
Betelgeuse, 259 f.;
distance from sun, 262.
Bible, climatic evidence in, 91 f.;
palms in, 92.
Binary stars, 252.
Birkeland, K., cited, 244.
Black Earth region, loess in, 159.
Boca, Cal., correlation coefficients, 83, 85.
Boltzmann, L., cited, 257.
Bonneville, Lake, 142, 143.
Borkum, storm-flood in, 99.
Boss, L. cited, 268, 269.
Botanical evidence of mild climates, 167 ff.
Boulders, on Irish coast, 119.
Bowie, W., cited, 293.
Bowman, I., cited, 213.
Britain, forests, 220;
level of land, 220.
British Isles, height of land, 111;
temperature, 216.
Brooks, C. E. P., cited, 115, 143, 196, 215, 225.
Brooks, C. F., cited, 209.
Brown, E. W., cited, 191, 244.
Brueckner, E., cited, 27.
Brueckner periods, 27 f.
Bufo, habitat of, 202.
Buhl stage, 216.
Bull, Dr., cited, 100, 101.
Butler, H. C., cited, 66, 67 ff., 70, 76.
California, changes of climate, *75;
correlations of rainfall, 86;
measurements of sequoias in, 73, 74 ff.;
rainfall, 108.
Cambrian period, 4 f.
Canada, storminess, 53 f., 57;
storm tracks in, 113.
Cape Farewell, shore ice at, 105.
Carbon dioxide, erosion and, 119 f.;
from volcanoes, 23;
hypothesis, 139;
importance of, 9, 11 f.;
in Permian, 148;
in atmosphere, 20, 96, 238;
in ocean, 226;
nebular hypothesis and, 232;
theory of glaciation, 36 ff.
Caribbean mountains, origin of, 193.
Carnegie Institution of Washington, 74.
Caspian Sea, climatic stress, 104;
rainfall, 107 f.;
rise and fall, 27;
ruins in, 71.
Cenozoic, climate, 266;
fossils, 21.
Central America, Maya ruins, 95.
Chad, Lake, swamps of, 171.
Chamberlin, R. T., cited, 166, 233, 269.
Chamberlin, T. C., cited, 19, 36, 38, 39, 42 f., 48, 122, 125,
152, 156, 190, 195, 227, 269.
Chandler, S. C., cited, 301.
Chinese earthquakes, periodicity of, 245.
Chinese, sunspot observations, 108 f.
Chinese Turkestan, desiccation in, 66.
Chronology, glacial, 215.
Clarke, F. W., cited, 226, 235.
Clayton, H. H., cited, 173 f.
Climate, effect of contraction, 189 ff.;
affect of salinity, 224;
in history, 64-97;
uniformity, 1-15;
variability, 16-32.
Climates, mild, causes of, 166-187;
mild, periods of, 274.
Climatic changes, and crustal movements, 285 ff.;
hypotheses of, 33-50;
mountain-building and, *25;
post-glacial crustal movements and, 215-222;
terrestrial causes of, 188-214.
Climatic sequence, 16 f.
Climatic stages, post-glacial, 270.
Climatic stress, in fourteenth century, 98-109.
Climatic uniformity, hypothesis of, 65, 71 f.
Climatic zoning, 169.
Cloudiness, glaciation and, 114, 147.
Clouds, as protection, 197.
Colfax, Cal., correlation coefficients, 83.
Cologne, flood at, 99.
Compass, variations, 150.
Continental climate, variations, 103.
Continents, effect on climate, 111 f.
Contraction, effect on climate, 189 ff., 199, 207;
effect on lands, 207;
heat of sun and, 13 f.;
irregular, 195;
of the earth, 18;
of the sun, 249;
stresses caused by, 310.
Convection, carbon dioxide and, 239.
Corals, in high latitudes, 21, 39, 167, 178.
Cordeiro, F. J. B., cited, 181, 183, 186.
Correlation coefficients, earthquakes and sunspots, 291;
Jerusalem rainfall and sequoia growth, 83 ff.;
rainfall and tree growth, 79 ff.
Cosmos, effect of light, 185.
Cressey, G. B., cited, 80.
Cretaceous, lava, 211;
mountain ranges, 44;
paleogeography, *201;
submergence of North America, 200.
Croll, J., cited, 34 ff., 176.
Croll's hypothesis, snow line, 139.
Crust, climate and movements of, 63, 287, 310;
movements of, 43;
strains in, 22.
Currents and planetary winds, 174.
Cycads, 169.
Cyclonic hypothesis, 97;
loess and, 163;
Permian glaciation and, 148;
snow line, 139.
Cyclonic storms, in glacial epochs, 140 f.;
solar electricity and, 243 (_see_ Storms, Storminess).
Cyclonic vacillations, 30 f.;
nature of, 57 ff.
Daily vibrations, 28 f.
Danube, frozen, 98.
Darwin, G. H., cited, 191.
Daun stage, 217.
Davis, W. M., cited, 271.
Davisson, C., cited, 294, 295, 299.
Day, C. P., cited, 239.
Day, length of, 18, 191.
Dead Sea, palms near, 92.
Death Valley, 142.
De Ballore, M., cited, 297, 298.
Deep-sea circulation, rapidity, 227;
salinity and, 176;
solar activity and, 179.
De Geer, S., cited, 215, 221.
De Lapparent, A., cited, 200.
Denmark, fossils, 271.
"Desert pavements," 161.
Deserts, abundant flora of, 171;
and pulsations theory, 88 ff.;
red beds of, 170.
Devonian, climate, 266;
mountains, 209.
Dog, climate and, 1.
Donegal County, Ireland, 220.
Double stars, 272, 280;
electrical effect of, 261.
Douglass, A. E., cited, 28, 73, 74 f., 84, 85, 107.
Dragon Town, destruction of, 104, 108.
Drake, N. F., cited, 297, 298.
Droughts, and pulsations theory, 87 f.;
in England, 102;
in India, 104 f.
Drumkelin Bog, Ireland, log cabin in, 220.
Dust, at high levels, 240.
Earth, crust of and the sun, 285-317;
internal heat, 212;
nature of mild climate, 274;
position of axis, 181;
rigidity of, 307;
temperature gradient, 213;
temperature of surface, 8.
Earthquakes, and seasons, 294, 297;
and sunspots, 288 f.;
and tropical hurricanes, 300;
and wandering of pole, 304 f.;
cause of, 307;
compared with departures from Eulerian position, 306;
seasonal distribution of, 299;
seasonal march, 295.
"Earthquake weather," 298.
East Africa, mild climate, 219.
East Indies, earthquakes of, 296.
Eberswalde, tree growth at, 102 f.
Ecliptic, obliquity of, 217.
Electrical currents, in solar atmosphere, 261.
Electrical emissions, variation of, 275.
Electrical hypothesis, 150, 250 f., 256 ff.
Electrical phenomena, storminess and, 56.
Electricity, and earthquakes, 292;
solar, 243.
Electro-magnetic hypothesis, 244.
Electrons, solar, 56;
variation of, 256.
Electro-stellar hypothesis, 274.
Elevation, climatic changes and, 39.
Engedi, palms in, 92.
England, climatic stress, 101 f.;
storminess and rainfall, 107.
Eocene, climate, 266.
Equinoxes, precession of, 96.
Erosion, storminess and, 309.
Eskimo, in Greenland, 106.
Eulerian movement, 301, 304.
Euphrates, 67.
Europe, climatic stress, 98 ff., 102 f.;
climatic table, 215;
glaciation in, 131;
ice sheet, 121;
inundations of rivers, 99;
post-glacial climate, 271;
rainfall, 107;
submergence, 196, 200.
Evaporation, and glaciation, 112, 114;
atmospheric pressure and, 237;
from plants, 179;
importance, 129;
in trade-wind belt, 117;
rapidity of, 224.
Evening primrose, effect of light, 184.
Evolution, climate and, 20;
geographical complexity and, 241;
glaciation and, 33;
of the earth, 311.
Faculae, cause of, 61.
False Point Lighthouse, barometric pressure at, 299.
Famine, cause of, 103;
in England, 101 f.;
in India, 104 f.;
pulsations theory and, 87 f.
Faunas, and mild climates, 168 f.;
in Permian, 152 f.
Fennoscandian pause, 216.
Flowering, light and, 184.
Fog, and glaciation, 116;
as protection, 197;
temperature and, 178.
Forests, climate and, 66.
Form of the land, 43 ff.
Fossil floras, and mild climates, 168;
in Antarctica, 273;
in Greenland, 273.
Fossils, 169, 230;
and loess, 158;
Archeozoic, 3 f.;
Cenozoic, 21;
dating of, 153;
glaciation and, 138;
in peat bogs, 271;
mild climate, 167;
Proterozoic, 4, 6 f.
Fourteenth century, climatic stress in, 98-109.
Fowle, F. E., cited, 45, 237, 238, 239.
Frech, F., cited, 36.
Free, E. E., cited, 142.
Freezing, salinity and, 224.
Fresno, rainfall record, 82.
"Friction variables," 247.
Frisian Islands, storm-flood, 99.
Fritz, H., cited, 109.
Frogs, distribution of, 202.
Fuchs, cited, 289.
Galaxy, 252.
Galveston, Tex., rainfall and temperature, 94.
Garner, W. W., cited, 183, 184.
Gasses, in air, 233.
Geographers, and climatic changes, 65 ff.
Geological time table, *5.
Geologic oscillations, 18 f., 21 ff., 188, 240.
Geologists, changes in ideas of, 64 f.
Germanic myths, 219.
Germany, forests, 220;
growth of trees in, 102;
storms in, 102.
Gilbert, G. K., cited, 143.
Glacial epochs, causes of, 268;
dates of, 216;
intervals between, 264 f.;
length of, 166 f.
Glacial fluctuations, 24 ff.;
nature of, 57 ff.
Glacial period, at present, 272;
ice in, 57 f.;
length of, 269;
list, 265;
temperature, 38.
Glaciation, and loess, 155 f.;
and movement of crust, 287;
conditions favorable for, 111;
extent of, 124;
hypotheses of, 33 ff.;
in southern Canada, 18;
localization of, 130 ff.;
Permian, *145;
solar-cyclonic hypothesis of, 110-129;
suddenness of, 138;
upper limit of, 141.
Goldthwait, J. W., cited, 271.
Gondwana land, 21, 204.
Gravitation, effect on sun, 250;
pull of, 244.
Great Basin, in glacial period, 126;
salt lakes in, 142.
Great Ice Age, see Pleistocene.
Great Plains, effect on ice sheet, 120.
Greenland, climatic stress, 105 ff.;
ice, 26;
rainfall, 108;
storminess, 57;
submergence, 219;
vegetation, 21, 37, 287;
winds, 135, 161.
Gregory, J. W., cited, 90 ff., 97.
Gschnitz stage, 216.
Guatemala, ruins in, 95.
Guervain, cited, 135.
Gyroscope, earth as, 181.
Hale, G. E., cited, 56, 62.
Hamdulla, cited, 104.
Hann, J., cited, 66.
Hansa Union, operations of, 100.
Harmer, F. W., cited, 115, 119.
Heat, and earthquakes, 292;
earth's internal, 18.
Hedin, S., cited, 88.
Heim, A., cited, 190.
Heligoland, flood in, 99.
Helland-Hansen, B., cited, 174.
Helmert, F. R., cited, 302.
Henderson, L. J., cited, 9, 10, 11, 12.
Henry, A. J., cited, 94, 208.
Hercynian Mountains, 45.
High pressure and glaciation, 115, 135.
Himalayas, glaciation, 144;
origin of, 193;
snow line, 139.
Himley, cited, 104.
Historic pulsations, 24 f.;
nature of, 57 ff.
History, climate of, 64-97;
climatic pulsations and, 26.
Hobbs, W. H., cited, 115, 125, 135, 161.
Hot springs, temperature of, 6.
Humphreys, W. J., cited, 2, 37 f., 45, 46, 50, 56, 238.
Hurricanes, in arid regions, 144;
sunspots and, 53.
Hyades, cluster in, 268.
Ice, accumulations, 57 f.;
advances of, 122;
distribution of, 131;
drift, 105.
Ice sheets, disappearance, 128;
limits, 120;
localization, 130 ff.;
rate of retreat, 165;
thickness, 125.
Iceland, submergence, 219.
Iowan ice sheet, rapid retreat, 165.
Iowan loess, 158.
India, drought, 104 f.;
famine, 104 f.;
rainfall, 108.
Indian glaciation, 266.
Inter-glacial epoch, Permian, 153.
Internal heat of earth, 212.
Ireland, Drumkelin Bog, 220;
in glacial period, 119;
level of land, 220;
storminess and rainfall, 107;
submergence, 219.
Irish Sea, tides, 191.
Irrigation ditches, abandoned, 97.
Isostasy, 307 ff.
Italy, southern, climate of, 86 f.
Japan, earthquakes of, 296.
Javanese mountains, origin of, 193.
Jaxartes, 108.
Jeans, J. H., cited, 251, 252, 253, 266, 272.
Jeffreys, H., cited, 302, 303, 306.
Jeffreys, J., cited, 191.
Jericho, palms in, 92.
Jerusalem, rainfall, 86;
rainfall and temperature, 94;
rainfall in, and sequoia growth, 83 ff.
Johnson, cited, 226.
Judea, palms in, 92.
Jupiter, and sunspots, 243;
effect of, 253;
periodicity of, 61 f.;
temperature of, 258;
tidal effect of, 250.
Jurassic, climate, 266;
mountain ranges, 44.
Kansas, variations of seasons, 103.
Kara Koshun marsh, Lop Nor, 104.
Keewatin center, 113;
evaporation in, 129.
Keewatin ice sheet, 121.
Kelvin, Lord, cited, 13 f.
Keyes, C. R., cited, 156.
Kirk, E., cited, 287.
Knott, C. G., cited, 294, 295, 297, 299, 304, 306.
Knowlton, F. H., cited 167, 169, 170, 212, 232.
Koeppen, W., 47, 52, 140.
Krakatoa, glaciation and, 48;
volcanic hypothesis and, 45.
Kruemmel, O., cited, 224, 228.
Kullmer, C. J., cited, 113, 115, 128;
map of storminess, *54.
_Kungaspegel_, sea routes described, 106.
Labor, price in England, 102.
Labradorean center of glaciation, 113.
Lahontan, Lake, 142.
Lake strands, _see_ Strands.
Lake Superior, lava, 211.
Lakes, during glacial periods, 141 f.;
in semi-arid regions, 60;
of Great Basin, 126;
ruins in, 97.
Land, and water, climatic effect of, 196 ff.;
distribution of, 200, form of, 43 ff.;
range of temperature and, 196.
Lavas, climatic effect of, 211.
Lawson, A. C., cited, 310.
Lebanon, cedars of, 83.
Leiter, H., cited, 71.
Leverett, F., cited, 271.
Life, atmosphere and, 229 f.;
chemical characteristic of, 12;
effect of salinity, 225;
of glacial period, 127;
persistence of forms, 230.
Light, effect of atmosphere on, 236;
effect on plants, 184 ff.;
ultra-violet, storminess and, 56;
variation of, 275.
Litorina sea, 218.
Loess, date of, 156 ff.;
origin of, 155, 165.
Lop Nor, rise of, 104;
swamps, 171.
Lows, and glacial lobes, 122;
movements of, 126;
see Storms and Cyclones.
Lulan, 104.
Lull, R. S., cited, 5, 188.
MacDougal, D. T., cited, 171.
McGee, W. J., cited, 156.
Macmillan, W. D., cited, 191.
Magdalenian period, 216.
Magnetic fields of sunspots, 56.
Magnetic poles, relation to storm tracks, 150.
Makran, climate, 89;
rainfall, 89.
Malay Archipelago, earthquakes of, 296.
Mallet, R., cited, 288.
Malta, rainfall, 86.
Manson, M., cited, 147.
Mayas, civilization, 26;
ruins, 95.
Mayence, flood at, 99.
Mazelle, E., cited, 224.
Mediterranean, climate of, 72;
rainfall records, 86;
storminess in, 60.
Mercury, and sunspots, 243.
Mesozoic, climate, 266;
crustal changes, 286;
emergence of lands, 287.
Messier, 8;
variables, 248.
Metcalf, M. M., cited, 202.
Meteorological factors and earthquakes, 300 f.
Meteorological hypothesis of crustal movements, 294.
Meteors, and sun's heat, 13, 246.
Michelson, A. A., cited, 259.
Middle Silurian, fauna in Alaska, 287.
Mild climates, _see_ Climates, mild.
Milky Way, 252.
Mill, H. R., cited, 228.
Milne, J., cited, 288, 290, 294, 304, 306.
Miocene, crustal changes, 287.
Mississippi Basin, loess in, 159.
Mogul emperor, and famine, 104.
Monsoons, character of, 146;
direction of, 208;
Indian famines and, 105.
Moulton, F. R., cited, 13, 258, 269.
Mountain building, climatic changes and, *25.
Mountains, folding of, 190;
rainfall, on, 208.
Multiple stars, 252.
Nansen, F., cited, 122, 174.
Naples, rainfall, 86.
Nathorst, cited, 169.
Nebulae, 247.
Nebular hypothesis, 232, 267.
Neolithic period, 218.
Nevada, correlations of rainfall, 86.
New England, height of land, 111.
New Mexico, rainfall, 89.
New Orleans, La., rainfall and temperature, 94.
New Zealand, climate, 177;
tree ferns, 179.
Newcomb, S., cited, 52.
Nile floods, periodicity in, 245.
Nitrogen, in atmosphere, 19.
Niya, Chinese Turkestan, desiccation at, 66.
Nocturnal cooling, changes in, 238 f.
Norlind, A., cited, 100.
Norsemen, route to Greenland, 26.
Norse sagas, 219.
North Africa, climate of, 71;
Roman aqueducts in, 71.
North America, at maximum glaciation, 122 ff.;
emergence of lands, 193;
glaciation in, 131;
height of land, 111;
interior sea in, 200;
inundations, 196;
loess in, 155;
submergence of lands, 19, 21.
North Atlantic Ocean, salinity, 228.
North Sea, climatic stress, 98 ff.;
floods around, 26, 99;
rainfall, 107;
storminess, 57.
Northern hemisphere, earthquakes of, 294.
Norway, decay, 100;
temperature, 177.
Novae, 247.
Oceanic circulation, carbon dioxide and, 39 ff.
Oceanic climate, characteristics, 103.
Oceanic currents, diversion, 44;
influence of land distribution, 203.
Oceans, age of, 223;
composition of, 223-241;
deepening of, 199;
salinity, 19, 223;
temperature, 6, 152, 180, 226.
Okada, T., cited, 224.
Old Testament, temperature, 92.
Orbital precessions, 27.
Ordovician, climate, 266.
Organic evolution, glacial fluctuations and, 26.
Orion, nebulosity near, 247;
stars near, 248.
Orontes, 67.
Osborn, H. F., cited, 216.
Owens-Searles, lakes, 142.
Oxus, 108.
Oxygen, in atmosphere, 20, 234;
in Permian, 152.
Ozone, cause of, 56.
Paleolithic, 216.
Paleozoic, climate, 266;
mountains in, 209.
Palestine, change of climate, 91 f.
Palms, climatic change and, 91 f.;
in Ireland, 179.
Palmyra, ruins of, 66.
Parallaxes of stars, 276 f.
Patrician center, 134.
Peat-bog period, first, 218.
Penck, A., cited, 139, 156, 157, 158, 269.
Pennsylvanian, life of, 26.
Periodicities, 245 f.
Periodicity, of climatic phenomena, 60 f.;
of glaciation, 268;
of sunspots, 243.
Permian, climate, 266;
distribution of glaciation, 152;
glaciation, 60, 144, *145, 226;
glaciation and mountains, 45;
life of, 26;
red beds, 151;
temperature, 146 f.
Perry, cited, 289.
Persia, lakes, 143;
rainfall, 89.
Pettersson, O., cited, 98 ff., 100 f., 103, 106, 219.
Pirsson, L. V., cited, 3, 196.
Planetary hypothesis, 253, 267.
Planetary nebulae, 252.
Planets, and sunspots, 243;
effect of star on, 255;
sunspot cycle and, 62;
temperatures, 8 f.
Plants, climate and, 1 f.;
effect of light, 184 ff.
Pleion, defined, 29.
Pleionian migrations, 29 f.
Pleistocene, climate, 266;
duration of, 48;
glaciation, 110 ff.;
ice sheets, *123.
Pluvial climate, causes of, 143;
during glacial periods, 141.
Po, frozen, 98.
Polaris, 272.
Polar wandering, hypothesis of, 48 f.
Pole and earthquakes, 305.
Post-glacial crustal movements and climatic changes, 215-222.
Poynting, J. H., cited, 8.
Precessional hypothesis, 34 f.
Precipitation, and glaciation, 114, 133;
during glacial period, 118;
snow line and, 139;
temperature and, 94.
Procyon, companion of, 280;
luminosity, 278;
speed of, 281.
Progressive change, 241.
Progressive desiccation, hypothesis of, 65 ff.
Proterozoic, 4 f.;
fossils, 6 f.;
glaciation, 18, 144, 226, 266;
lava, 211;
mountains in, 209;
oceanic salinity, 42 f.;
oxygen in air, 234;
red beds, 151;
temperature, 146 f.
Pulsations, hypothesis of, 65, 72 ff.
Pulsatory climatic changes, 72 ff.
Pulsatory hypothesis, 272.
Pumpelly, R., cited, 271.
Radiation, variation of, 275.
Radioactivity, heat of sun and, 14 f.
Rainfall, changes in, 93 f.;
glaciation and, 50;
sunspots and, 53, *58, 59;
tree growth and, 79.
Red beds, 151, 170.
Rhine, flood, 99;
frozen, 98.
Rho Ophiuchi, variables, 248.
"Rice grains," 61.
Richardson, O. W., cited, 256.
Rigidity, of earth, 307.
Roads, climate and, 66.
Rogers, Thorwald, cited, 101.
Romans, aqueduct of, 71.
Rome, history of, 87.
Rotation, of earth, 18 f.
Ruden, storm-flood, 99.
Rugen, storm-flood, 99.
Ruins, as climatic evidence, 66;
rainfall and, 60.
Sacramento, correlation coefficients, 82 f., 85;
rainfall, 86;
rainfall record, 79.
Sagas, cited, 105 f.
St. John, C. E., cited, 236.
Salinity, deep-sea circulation and, 176;
effect on climate, 224;
in North Atlantic, 228;
ocean temperature and, 226;
of ocean, 19, 120.
Salisbury, R. D., cited, 111, 125, 129, 139, 156, 206, 269, 271.
Salt, in ocean, 223.
San Bernardino, correlation of rainfall, 85.
Saturn, and sunspots, 243;
sunspot cycle and, 62.
Sayles, R. W., cited, 183.
Scandinavia, climatic stress, 100 f.;
fossils, 271;
post-glacial climate, 271;
rainfall, 107;
storminess, 57, 107;
temperature, 216.
Scandinavian center of glaciation, 113.
Schlesinger, F., cited, 275, 278, 298, 301, 305.
Schuchert, C., cited, 3, 5, 23, *25, *123, 138, *145, 168, 169,
172, 188, 193, 196, 198, 200, *201, 206, 211, 230, 265.
Schuster, A., cited, 61, 244, 294, 296.
Sculpture, Maya, 96.
Sea level and glaciation, 119.
Seasonal alternations, 28 f.
Seasonal banding, 183 f.
Seasonal changes, geological, 183.
Seasons, and earthquakes, 294, 295, 297, 299;
evidences of, 169.
Secular progression, 17 ff., 188.
Seistan, swamps, 171.
Sequoias, measurements of, 74 ff.;
rainfall record, 79.
Setchell, W. A., cited, 1.
Shackleton, E., cited, 125.
Shapley, H., cited, 246, 247, 254, 256, 275.
Shimek, E., cited, 157, 161.
Shreveport, La., rainfall and temperature, 93 f.
Shrinkage of the earth, 190.
Siberia, and glaciation, 132.
Sierras, rainfall records, 82.
Simpson, G. C., cited, 222.
Sirius, companion of, 280;
distance from sun, 262;
luminosity, 278;
speed of, 281.
Slichter, C. S., cited, 192.
Smith, J. W., cited, 73.
Snowfall, glaciation and, 50, 114.
Snowfield, climatic effects of, 115.
Snow line, height of, 138;
in Andes, 139;
in Himalayas, 139.
Solar activity, cycles of, 245;
deep-sea circulation and, 179;
ice and, 134.
Solar constant, 114.
Solar-cyclonic hypothesis, 51-63, 287;
glaciation and, 110-129.
Solar prominences, cause of, 61.
Solar system, 252;
conservation of, 243;
proximity to stars, 63.
Solar variations, storms and, 31.
South America, earthquakes, 301.
South Pole, thickness of ice at, 125.
Southern hemisphere, earthquakes, 296;
glaciation in, 131 f.
Southern Pacific railroad, rainfall records along, 82.
Soy beans, effect of light, 185 f.
Space, sun's journey through, 264-284.
Spiral nebulae, 251 f.;
universe of, 267.
Spitzbergen, submergence, 219.
Springs, climate and, 66.
Stars, approach to sun, 253;
binary, 252;
clusters, 252, 268;
effect on solar atmosphere, 63;
dark, 254;
parallaxes of, 276 f.;
tidal action of, 249.
Stefan's Law, 257.
Stein, M. A., cited, 78.
Stellar approaches, probability of, 260.
Storm belt in arid regions, 144.
Storm-floods, in fourteenth century, 99.
Storminess, and erosion, 309;
and ice, 134;
effect on glaciation, 112;
sunspots and, 163;
temperature and, 94, 173.
Storms, blows of, 300, 302;
increase, 60;
movement of, 125 f.;
movement of water and, *175;
origin of, 30 f.;
sunspots and, 28, 53;
_see_ Cyclones and Lows.
Storm tracks, during glacial period, 117;
location, 113;
relation to magnetic poles, 150;
shifting of, 119.
Strands, climate and, 66;
in semi-arid regions, 60;
of salt lakes, 142.
Suess, E., cited, 192.
Sun, and the earth's crust, 285-317;
approach to star, 253;
atmosphere of, 61, 274;
atmosphere of, and weather, 52;
cooling of, 49;
contraction of, 249;
disturbances of, 172;
effect of other bodies on, 242-263;
heat, 13;
journey through space, 264-284;
Knowlton's hypothesis of, 168.
Suncracks, 232.
Sunspot cycles, 27 f.
Sunspots, and earthquakes, 289;
causes of, 61;
magnetic field of, 261;
maximum of, 109;
mild climates and, 172;
number, 108 f.;
periodicity, 243;
planetary hypothesis of, 253;
records, 245;
storminess and, 163;
storms and, 300;
temperature of earth and, 52, 173.
Sunspot variations, 282.
Swamps, as desert phenomena, 171.
Sylt, storm-flood, 99.
Syria, civilization in, 67;
inscriptions in, 76;
Roman aqueducts in, 71.
Syrian Desert, ruins in, 66.
Talbert, cited, 213.
Tarim Basin, red beds, 151.
Tarim Desert, desiccation, 66.
Tarim River, swamps, 171.
Taylor, G., cited, 140, 144, 191, 271.
Temperature, change of in Atlantic, 174;
changes in, 93;
climatic change and, 49;
critical, 9;
geological time and, 3;
glacial period, 38;
glaciation and, 42, 132, 139;
gradient of earth, 213;
of ocean, 180;
in Norway, 177;
in Permian, 146 f.;
in Proterozoic, 146 f.;
limits, 6 ff.;
precipitation and, 94;
range of, 3, 8;
solar activity and, 140;
storminess and, 94, 112, 173;
sunspots and, 28, 173;
volcanic eruptions and, 46;
zones, 172.
Terrestial causes of climatic changes, 188-214.
Tertiary, lava, 211.
Thames, frozen, 98.
Thermal solar hypothesis, 49 f., 97.
Thermo-pleion, movements of, 30.
Thesis, of pulsations, 24.
Thiryu, storm-flood, 99.
Tian-Shan Mountains, irrigation in, 71.
Tidal action of stars, 249.
Tidal effect, of Jupiter, 253;
of planets, 244.
Tidal hypothesis, 251.
Tidal retardation, effect on land and sea, 191;
rotation of earth and, 18 f.;
stress caused by, 310.
Tides, cycles of, 219.
Time, geological, _see_ Geological time.
Toads, distribution of, 202.
Tobacco plant, effect of light, 184.
Topography, and glaciation, 132.
Transcaspian Basin, red beds, 151.
Tree ferns, in New Zealand, 179.
Tree growth, periodicity in, 245;
rainfall and, 79.
Trees, in California, 219;
measurement of, 73 ff.
Triassic, climate, 266.
Trifid Nebula, variables, 248.
Trondheim, wheat in, 101.
Trondhenaes, corn in, 101.
Tropical cyclones, in glacial epochs, 140 f.;
occurrence, 148;
solar activity and, 113.
Tropical hurricanes, earthquakes and, 300;
sunspots and, 149.
Turfan, temperature, 17.
Turner, H. H., cited, 245.
Tyler, J. M., cited, 216.
Tyndall, J., cited, 36, 37.
Typhoon region, "earthquake weather," 298.
Typhoons, occurrence, 300.
United States, rainfall and temperature in Gulf region, 93 f.;
salt lakes in, 142;
southwestern, climate, 66;
storminess, 53 f., 60.
Variables, 247.
Veeder, M. A., cited, 300.
Vegetation, theory of pulsations and, 90.
Venus, atmosphere of, 236.
Vesterbygd, invasion of, 106.
Vicksburg, Miss., rainfall and temperature, 93 f.
Volcanic activity, climate and, 210;
movement of the earth's crust and, 285;
times of uplifting lands and, 23.
Volcanic dust, climatic changes and, 97.
Volcanic hypothesis, climatic change and, 45 ff.;
snow line, 139.
Volcanoes, activity of, 96.
Volga, 108.
Walcott, C. D., cited, 4, 230.
Wandering of the pole, 302.
Water, importance, 9.
Water vapor, condensation of, 56;
effect on life, 231;
in atmosphere, 19.
Wave, effect on movement of water, 176.
Weather, changes of, 31 f.;
origin of, 174;
variations, 52.
Wells, H. G., cited, 35.
Wendingstadt, storm-flood, 99.
Westerlies, 21 f.
Wheat, price in England, 102.
White Sea, submergence, 219.
Whitney, J. D., cited, 142.
Wieland, G. R., cited, 169.
Williamson, E. D., cited, 226.
Willis, B., cited, 206.
Winds, at ice front, 162;
effect on currents, 174;
glaciation and, 133;
in Antarctica, 161;
in glacial period, 119;
in Greenland, 161;
planetary system of, 174;
velocity, 240.
Witch hazel, effect of light, 184.
Wolf, J. R., cited, 61, 109, 288.
Wolfer, cited, 244.
Wright, W. B., cited, 35, 111, 119.
Writing, among Mayas, 96.
Yucatan, Maya civilization, 26, 107;
rainfall, 108;
ruins, 95.
Yukon, Ice Age in, 221.
Zante, earthquakes of, 296.
Zonal crowding, 117.
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