Air, 13, 32 compression of, 17 cooling of, 16, 17 heating of, 16, 17, 61 in motion, 170 in weathering, 169 moisture in, 57 Air brake, 19 Airplane, 346 Air pressure, 21, 24 Alcohol, 192, 220, 471, 491 Aldebaran, 100 Alfalfa, 396 Alloy, 181 Alluvial soil, 172 Aluminum bronze, 182 Amber, 243 Ameba, 450 Ammonia, liquid, 144 Ammonium chloride, 254 Andirons, 62 Anemia, 210 Animals, 422, 423 Anthracite, 186 Ants, 441 Arbor day, 415 Armature, 234, 263, 265, 272 Arteries, 477, 479, 480 Ashes, 29 Assimilation, 474 Atmosphere, 21, 77, 163 composition of, 78 Automobile, 358 Axe, 326 Axil of leaf, 374 Backbone, 499 Backlog, 62 Bacteria, 41, 222, 223, 381, 415, 490 Baking, 214, 217 Baking Powder, 218 Balance, sense of, 318 Baling press, 339 Bamboo, 389, 393 Banana, 402 Barley, 390 Bases, 194 Bathing, 493 Battery, 255 storage, 256 Beasts of burden, 425 Bedrock, 163 Bees, 440 Bell, electric, 262 Berries, 401 Biceps, 334, 459 Cone-bearing plants, 382 Connective tissue, 431, 453, 459, Constellation, 98, 99 Convection, 64 Cooking, 214 Copper, 182 Corpuscles, 452, 475, 482 gin, 399 Cottonseed oil, 399 Crane, 62, 261, 336 Crops, 174, 176 Cross section of tree, 407 Currents, electric, 249 Cyclone, 86 Dairying, 175 Decay, 40, 41, 49 Declination of compass, Degree of heat, 71 Density, 115 Dermis, 431, 492 Derrick, 336 Developing, 289 Dew and dew point, 78 Diamond, 184 Diaphragm, 457 Dietetics, 471 Digestion, 214, 463 240 Epiglottis, 487 Erosion, 167 Esophagus, 467, 487 Evaporation, 144 Evergreens, 413 Excretion, 483 Fabrics, 398 Fermentation, 191 Ferments, 464, 468 Ferns, 382 Fertility of soil, 175 Field, magnetic, 238, 262 Fire, 26, 27, 28 engine, 47 Fireless cooker, 76 Fishes, 437 Fixed stars, 99 Flatiron, electric, 267 Flax, 199, 399 Flint and steel, 27 Flowers, 377 Fly, 443 trap, 443 Focus, 286, 289 Fog, 80, 357 Food, 206, 214 of plants, 366 preserving of, 222 Grate, 62 Gravitation and gravity, 113 substances, 398 Habits, 503 Hail, 81 Hair, 492 Hammer, pneumatic, 19 Hard water, 160 Hardwood, 412 Hearing, 315, 499 Heart, 477 wood, 409 Heat, 28, 71 from electricity, 267 Heating, 61 Heavenly bodies, 95 preparation of, 130 Hydrogen peroxide, 37 Hydroplane, 348 Ice, 144, 170 cream, 145 Illuminated bodies, 277 Indirect lighting, 309 |