402 



ELEMENTS OF GENERAL SCIENCE 



Night, length of, 36 



Nitrogen, 69, 73, 74, 268, 291-292, 

 330; as fertilizer, 86; loss from 

 soil, 292 ; supply of, 292, 293 



Norther, 48 



Nutrition, 361-362 ; hygienic aspects 

 of, 356-362 



Oakwood, 140 



Offspring and parent, *383-395 



Ohm's Law, 206 



Olive oil, 140 



Orion, 273, 274*, 275 



Osmometer, 322* 



Osmosis, 323 



Overeating, 357 



Overproduction, 375-377 



Oxygen, 66, 67, 69, 73, 82, 268, 291 



Pain a danger signal, 357 



Palisade, 81 



Paraffin, 119 



Parallel circuit, 202-203* 



Parasite, 84*, 91*, 92*, 813 



Parent and offspring, *383-395 



Pasteurization, 101 



Peach-growing and climate, 160 



Peanut seedling, 372* 



Peat, 289, 290 



Pegasus, 272 



Perspiration, 123-124 



Petiole of leaf, 78 



Phaethon, 278 



Phosphorus, 69, 208, 291, 330 



Photomicrographs of bacteria, 93* 



Photosynthesis, 83, 84, 85, 192, 329 



Pine wood, 140 



Pistil, 370, 371* 



Pittsburgh, typhoid death rate in, 

 165 



Planets, *251-261, 268 



Plant associations, 817* 



Plant compared to factory, 85 



Plant covering of the earth, 815- 

 327* 



Plant food, raw materials, 76, 77, 

 291 ; where made, 77 



Plant formations, 316-318 



Plant synthesis, importance of, 86 



Plants, abundance of, 316-816 ; cul- 

 tivated, 321 ; dependent, 91* ; re- 

 production of, 863-866, 869-373; 

 as soil-formera, 286-286, 290 ; 

 variety of, 316-318 



Platinum, 69, 119, 140 



Pleiades, 270, 275 



Plumbing, house, 166 



Pneumatic tire, 3, 6, 12 



Pneumonia, 95 



Pole Star, 269, 271-273 



Pollution of water supply, 162-172 



Pollux, 273 



Pond scum, reproduction of, *364- 

 366 



Portages, 156*, 157 



Potassium, 69, 268, 291 



Prsesepe, 273 



Pressure, of liquids, *128-140 ; trans- 

 mission of, in liquids, *132-136 ; 

 of water at faucets, 166 



Pressure gauge, 6*, 185 



Procyon, 273 



Protein, 292, 329, 330, 891 ; manu- 

 facture of, 85-86 



Protoplasm, 81, 823, 365 



Ptyalin, 338 



Pulley, 175, 177*, *178-181; mechan- 

 ical advantages of, 180 



Pumps, 4*, 6, *129-131 



Quito, Ecuador, 116 



Rabbit, overproduction of, 881-382 



Race, future of the, 894 



Ragweed, variation in, 884-386 



Railroads, 157 



Rainfall in the United States, 64, 

 66 



Raspberry, 373* 



Reclamation of swamp lands, 803 



Refrigerator, 19*, 20, 126 



Regulus, 276 



Reproduction, *363-873 ; in birds 

 and mammals, 869; vegetative, 

 378 



Reservoirs for water storage, 166 



Respiration, 842, 343 ; and assimila- 

 tion, 334-336 



Rigel, 274 



Rings of Saturn, 268* 



Rock, becomes soil, *279-287 ; dis- 

 integrated by water, 282 ; effect of 

 water on, 281* 



Roosevelt Dam, 801* 



Root hairs, 323*, 824* 



Root structure, *323-324 



Roots, surface of, *324-326 



Royal Observatory of England, 259, 

 260 



Rural water supply, 169-171 



