INDEX 



Abdomen, of insects, 279 

 Aeration, 93 

 Air, i, 166, 167 



a mixture of gases, 43 



composition of, 151, 156 



entering water, 42 



expansion of, 180, 181 



movements of, 19 

 Air-pressure (see atmospheric pres- 

 sure) 



Algae, 249, 258 

 Aneroid barometer, 58 

 Animals, i, 270-275 



jointed-legged, 270 



vertebrates, 270 

 Antarctic Circle, 176 

 Antennae, 278 

 Anticyclone, 193 



Archimedes (287-212 B. C.) prin- 

 ciple, 63, 64 

 Arctic Circle, 176 

 Artesian wells, 33, 52 

 Astronomy, 172 

 Atmosphere, 3 



convection currents of, 167 



defined, 147 



density of, 148, 149 



humidity of, 143 



in indoor life, 199 



relation to heat, 150, 167 



relation to sun, 162 



weather, a state of, 178 

 Atmospheric pressure, 55-62 



at mountain tops, 59 



at sea-level, 59 



cyclones, 192 



high and low, 180 



measuring, 58 



relation to water vapor, 184 



Bacteria, 101-104 

 Barometer 



aneroid, 58, 59 



high and low pressures, 180 



mercurial, 59, 61 



Caloric, 124 



Calorimeter, 133, 134 



Calory, 132, 143 



Cancer, Tropic of, 175, 176 



Candle-power, 228 



Capricorn, Tropic of, 175, 176 



Carbohydrates, 230, 234, 238 



Carbon, 159 



Carbon dioxide, 43, 153, 154, 156, 



158 



Cells, 244 



Centigrade thermometer, 130 

 Chlorophyll, 238 

 Cistern, 46 

 Clay, 52, 84, 94, 96 

 Clouds, 4 



cirrus, 197 



cumulo-nimbus, 197 



stratus, 197 

 Coal, 3, 50 

 Cold, 135-140 



freezing, 136 

 Color, 216-224 



rainbow, 220 



solar spectrum, 220 



waves, 220 

 Combustion, 209-215 



burning, 209 



energy released by, 214 



products of, 213 



rusting, 209 

 Condensation, 13, 16, 18, 143 

 Contraction, 12, 89, 129, 141, 144 

 Convection, 145, 167, 180 

 Convection currents, 167, 180 

 Crustacea, 270 



Cycle, of life, 233 



nutritive, 236 

 Cyclones, 192 



anticyclone, 193 



Day, 169, 174 



Degree, of latitude and longitude, 



175 

 Deposition, 25 



285 



