INDEX 



"A" battery, 282 



Abbott, C. G., 168 



Absorption, of digested food, 95; of ultra- 

 violet light, 106 



Acceleration, 147 



Accommodation of the eye, 113 



Acquired characteristics, 236 



Acquired immunity, 218 



Adulteration of foods, 90, 91 



Ai:des, 223 



Aeration of water, 60 



Aerial, 277 



African sleeping sickness, 219 



Agents of erosion : ground water, 203 ; 

 running water, 203 ; wind, 204 



Age of earth, 196 



Ailerons, 308 



Air, composition of, 21, 23 ; and the hu- 

 man voice, 19; unequal heating of, 

 38, 51; depth of, 4, 46; compressed, 

 13; effect of altitude on pressure of, 

 5; effect of heating, 38, 39; explora- 

 tion of, 1, 4; importance of, 1; in 

 breathing, 11 ; in burning, 22, 24; meas- 

 urement of pressure of, 2, 5; occupies 

 space, 3; uses of, 1, 10, 11; weight of, 

 2; chemical effects of on earth's crust, 

 203 



Air brake, 14, 301 



Air conditioning, in homes, 25, 135 ; in 

 railroad coaches, 300 



Air hammer, 13 



Air lift, 13 



Airplane, action of air currents on, 311 ; 

 achievements of, 312; control of, 311; 

 early history of, 310, 311; in transpor- 

 tation, 313; parts of, 312; principle of, 



3 1 1 



Air pump, 9, 17 



Airships, 309, 3.10, 314 



Air thermometer, 43 



Alcock and Brown, 312 



Alloy, 246 



Alphabet, development of, 265 



Alpha centauri, 174 



Alternating current, 250 



Altimeter, 6 



Altitude, 2, 51 ; effect on climate, 51 



Altitude records, airplane, 312 ; balloon, 1 



Amelia, 229 



Ammeter, 260 



Ammonia ice plant, 32 



Ammonium chloride, 239, 242 



Ampere, 258 ; and electric current, 260 



Ampere, A.M., 260 



Amplify, 284 



Anemometer, 45 



Aneroid, 2 ; barometer, 2, 5 



Angle of incidence, 105 



Angle of reflection, 105 



Animal pests, 223 



Animals, breathing of, 24; parts eaten, 78; 

 of the past, 199; breeding, 236; im- 

 provement of, 236 



Anopheles, 223 



Antarctica, 246 



Antarctic circle, 55 



Antenna. 282 



Anther, 231 



Anthracite, 122 



Anticyclone, 38, 40 



Antiseptic, 71, 215 



Antitoxin, 215 218 



Anvil, 19 



Aquarium, 25 



Aqueduct, 64, 68 



Aqueous humor. 113 



Archimedes, 158, 304 



Archytos, 308 



Arc lamp, 82, 102, 256 



Arctic circle, 55 



Argon, in the air, 23 ; in electric bulbs, 23, 

 102 



Armature, 246; of generator, 250; of mo- 

 tor, 257; of telegraph sounder, 268 



Artery, 92, 95 



Artesian wells, 64 



Artificial ice, 32 



Artificial silk, 143 



Assimilate, 92 



Asteroids, 179 



Astigmatism, 113 



Astrology, 170 



Astronomy, 170 



Atmosphere, nature of, 3 ; pressure of, 5 ; 

 rare gases in, 23 ; water-holding ca- 

 pacity of, 30; water vapor in, 23 



Atmospheric moisture, influences evapora- 

 tion, 29, 31 ; relation to saturation, 31 ; 

 sources of, 30 



Atom, 239 



Atomize, 294 



Atomizer, 10 



Audio frequency, 282 



Audion, 282 



Australian lady bird, 226 



Autogyro, 313 



Automobile, and development of roads, 



, 293 ; a means of transportation, 294 ; 



chassis of, 294; cooling system of, 295; 



power transmission system of, 294, 296 



Automobile gear shift, 297 



Automobile pump, 9 



Autumnal equinox, 191 



Axis, 186; inclination of earth's, 52 



Aztec methods of communication, 265 



Bacteria, 57, 80, 89, 216; and the souring 

 of milk, 85 ; that cause food to spoil, 

 87; experiment with, 215, 216; impor- 

 tance of to man, 217; relation of to dis- 

 ease, 218; entrance of in human body, 

 219 



Bacteriology, 215 



Balanced diet, 84 



Ballast, 303 



Balloon, sounding, 4 ; history of, 308 ; dir- 

 igible, 309 



Baltimore and Ohio, 299 



Barograph, 6 



Barometer, types of, 5; aneroid, 5; uses 

 of, 6; in weather forecasting, 45 



Battery, 240; "A" and "B" types, 282 



Bedbugs, 224 



Bed rock, 198 



Beetle, 226 



Bell, Alexander Graham, 273 



Bell, electric, 272-3 



Bends, 15 



Beri-beri, 83 



Bevaims, Maurice, 309 



Bichloride of mercury, 219 



Bicycle pump, 9 



Bile, 93 



Biological control of insect pests, 226 



Blood, composition of, 95; circulation of, 

 95 



Boiler scale, 61 



Boiling, as rapid evaporation, 34; effect of 

 on bacteria, 60 ; effect of on hard water, 

 61 



Borax, as a water softener, 61 



Bourscul, Charles, 273 



Boyle, Robert, 13 



Branca's engine, 164 



Branly, Professor, 280 



Bread, composition of, 81 



Breathing, air pressure in, 11 



Breezes, land and sea, 41 



British thermal unit, 128 



Broadcasting station, 284 



Broiling, 88 



Brown tail moth, 225 



Bubonic plague, 224 



Bunsen burner, 99 



Buoyancy, 303 



Burbank, Luther, 237 



Burning, products of, 22; nature of, 24; 



of candle, 98 



Buses, in transportation, 299 

 Byrd, Admiral Richard, 286 



Cables, ocean, 270 



Caisson, 12; uses of, 14; diagram of, 15 



Calcium compounds, 61 



Calorie, 126 



Camera, pinhole, 103; parts of, 111; prin- 

 ciple of, 114 



Cancer, Tropic of, 191 



Candle, burning of, 98; light from, 100; 

 structure of flame, 100 



Candle power, 108 



Canning, as a method of food preserving, 

 89 ; cold pack, 89 



Capillaries, 95 



Capillarity, 98; in a wick, 99, 100; in soil, 

 209 



Capricorn, Tropic of, 191 



Carbohydrate, 80, 81 



Carbolic acid, 219 



Carbon, in foods, 83; in candle, 100; in 

 telephone transmitter, 274 ; in coal, 122 ; 

 in electric bulb filaments, 102 



Carbon dioxide, preparation of, 22; in the 

 air, 23; in photosynthesis, 78; as a 

 product of combustion, 121 ; and ero- 

 sion, 203 



Carbon monoxide, 25 



Carbonic acid, 203 



Carboniferous period, 122 



Carbon tetrachloride in fire extinguisher, 

 140 



Carburetor, 291. 292 



Carrier wave, 282 



Cartridge fuses, 255 



Cassiopeia, 173 



Cavendish, Henry, 308 



Cell, electric, 240 



Cells, and growth, 77 ; division of, 77 ; 

 types of, 77, 230; and living things, 229 



Center of gravity, 305 



Centigrade, 43 



Centrifugal force, 48, 146, 148, 153 



Cepheus, 173 



Cerium, 101 



Cesspools, 74 



Chappe, 267 



Charging storage cells, 243 



Chassis, 291, 294 



Chemical change, 23 ; and heat energy, 120 



Chemical toilet, 76 



Chemical treatment of water, 65-9 



Chemical weathering, 203 



Chinese, early methods of communication 

 of, 265 



Chlorinated lime, 59 



Chlorine, in water sterilization, 59, 66 



Chlorophyll, 76 ; in photosynthesis, 78 



Circuits, electric for home, 255 ; short, 255 



Cirrus clouds, 33, 36 



Cistern. 63 



Clay, 209 



Clermont, 304 





