200 INDEX 



Geikie, A., 76 

 Generation, aequivocal, 91 



spontaneous, 90, 91 

 Geologic column, 60, 67 



history, 108 



record, 70 



time, eras of, 63 



time, length of, 80 



time, ratios of, 69 



time-table, 45 

 Geosynclines, 61, 62 

 Germany, optimum temperature in, as 



shown by death-rate, 167 

 Gibbon, 139, 140, 141, 142, 144 

 Gills, 120 

 Glacial deposits, 54, 56 



period, 46, 184 



period, effect of, on man, 149 



periods, 55, 183 

 Gorilla, 139, 140, 142 

 Grand Canyon revolution, 111, 118 

 Granite, 37, 40, 49, 75 

 Graphite, 63, 113 

 Grasses, expansion of, 136 



used for food by man, 143 

 Gravitation, 97 

 Grazing mammals, expansion of, 137 



mammals, origin of, 111 



mammals, rise of, 136 

 Greece, 147, 175 

 Greeks, 89, 191 



Habitats, organic, variability in, 78 

 Hands, as organs of the mind, 143 

 Haughton, S., 69 

 Health, best climatic conditions for, 



158 



effect of storms on, 166 

 Helmholtz, H. L. F. von, 10, 96, 98 

 Helmont, J. B. van, 90 

 Henderson, L. J., 88 

 Herds, 178 



Himalayan uplift, 146 

 Himalayas, 74 



Holmes, A., 52, 57, 60, 61 



Homo (Eoanthropus) daiusoni, 142 



Hopi Indians, 152, 154, 180 



Hornets, 90 



Horses, 74, 136, 137, 177, 178 



Hottentots, 150 



Human progress, factors in, 147 



Humboldt, A. von, 182 



Hunters, 151, 154, 177 



Huxley, T. H., 54, 107 



Hydrogen, 102 



Hydrosphere, 50, 51, 55, 63, 75 



Hylobates lar, 144 



Ice age, Permian, 51 



age, Proterozoic, 51 

 Igneous rocks, 43, 75 



rocks, as source of oceanic salts, 56 



rocks, erosion of, 32 

 Imagination, scientific, 106 

 Impact, effects of, 28 

 India, 179 



irrigation in, 180 

 Indian corn, 154 

 Indians, American, 148, 151, 153, 177 



California, 152, 153, 154 



Hopi, 152, 154, 180 



New Mexico, 152 



Pueblo, 152, 154 



Utah, 152 



Ute, 152, 153, 154 

 Indo-China, 188 

 Infusions, organic, 93 



sterilization of, 92 

 Insectivores, 136 

 Insects, 73, 89 

 Intervals, time, 71, 73 

 Invertebrates, distinguished from ver- 

 tebrates, 114 



evolution of, 114 

 Iron, 155 



compounds of, 102 



discovery of use of, 175 



limits to use of, 155 



