Activity, mental, optimum temperature

for, 172

physical, optimum temperature for,

172

Adelochordates, 117
Africans, 148, 149

Agriculture, 153, 154, 177, 178, 180
Air currents, changes in, 73
Alaska, coal in, 155
Alchemists, 82, 95
Algæ, 63, 113

Allantois, 126, 128
Allen, F. J., 101
Allosaurus, 133
a Centauri, 7, 8
Alps, rise of, 74
Alumina, 100

Alveolar substance, of protoplasm, 83
Amblypods, 134, 136

American Indians, 148, 151, 153, 177
Amino acids, 85

Ammonia, 99, 102
Ammonites, 73

Ammonium carbonates, 107

Amnion, 126, 128

Amphibia, 125

origin of, 65, 111

Amphioxus, 117

Animals, domestic, 177, 178
lime-secreting, 113
wild, taming of, 177
Ankylosaurs, 132
Annelids, 113

Apes, anthropoid, 139, 141

origin of, 111
Appalachian Mts., 78

revolution, 111, 127

trough, 78

Arabians, 150

Arboreal habitat, forsaking of, for
terrestrial, 142

Archæocyathinæ, 113

Archeopteryx, 129, frontispiece
Archean, beginning of, 43
Archeozoic era, 46, 49, 50, 56, 63

era, time ratio of, 69

sediments, thickness of, 63, 67

Arctic climate, effect of, on man, 149
Aridity, 123, 126, 127, 129, 136

Devonian, 143

Miocene, 143, 146

Mississippian, 145

Permian, 145

Pliocene, 143

Aristotle, 86, 89, 91
Arrhenius, S., 97, 98
Arthropods, 114

Asia, as home of domestic animals, 178
as primitive home of man, 149

as theater of mammalian evolution,
142

Asteroids, see planetoids

Asthenosphere, 41

Athenians, 147

Atmosphere, 54, 57, 75, 80

in Archeozoic, 63

of growing earth, 51

of water-gas, 35

origin of, 50

primordial, 34

Atmospheric blanket, of earth, 54

Atoms, 100, 101, 102

Australians, native, 150

Azoic era, time ratio of, 69

Bacteria, 96, 97

Baker, H., 91

Balanoglossus, 117

Earth, origin of, 46

outer shell of, 40

passage of, from molten into rigid

state, 36

place of, in universe, 4

positive areas in surface of, 50
primordial molten state of, 26, 33
readjustments in, 70, 71

shrinkage of, 48, 70, 71, 80, 109
sub-crustal shell of, 40
tidal strains in, 30

warping of, 70, 109
Echinoderms, 114
Eels, 90

Efficiency, effect of climate on, 156
Eggs, 126

Egypt, 90, 97, 179, 181, 182
Elephants, see Proboscidea
Energy, as factor in human progress,

147, 155, 173, 174, 192
distribution of, on basis of climate,
173

electric, of chemical elements, 105
heat, 105

to what due, 156

"Energy traffic," 85, 102

England, iron in, 155

Englishmen, 148

Environment, changes in, 73
fitness of, 88

Enzyme theory, of Troland, 103

Enzymes, autocatalytic, 103

catalytic power of, 104

evolution of, 106

Eocene time, 46, 111, 137, 138, 145, 146

time, climate of, 55

Eopaleozoic time, 79

Epi-Proterozoic interval, 119

Eras, duration of, 67, 68

Erosion, 32, 40, 54, 56, 57, 58, 60, 70,

76, 78, 110

Erpetoichthys, 122

Eskimos, 151

Europeans, modern, 154

Evolution, 73, 98
crises of, 112

cycles of, 80, 81

organic, 101

Fats, 84

Finland, optimum temperature in, as
shown by death-rate, 167, 169
Finns, 169, 171

Fire, discovery of use of, 174, 175
life derived from, 99
Fish forms, 116

Fishes, 81, 89, 119, 123

Age of, 46

origin of, 65

Flight, true, evolution of, 128
Floras, origin of, 65

Flying dragons, 73

Food, dependence of, on climate, 154,

155

effect of, on energy, 156
use of fire in cooking, 175
Foot, reptilian, 124

terrestrial, evolution of, 123
terrestrial, origin of, 111

Footprint, earliest known, 123, 124,

144

Footprints, Connecticut Valley, 130
Upper Triassic, 129
Formative era, 46, 47, 49, 50

era, earth-growth in, 47

era, volcanism in, 48

Fossils, 59

living, 81

France, deaths in, 160, 164, 165

Gabbro, 39

Gadow, H., 131

Galaxy, see Milky Way

Gale, H. S., 185

Galton, F., 147

Ganoids, 122
Gautama, 182