Chapter XXI: 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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