INDEX 



307 



Photomicrographs of bacteria, 85* 



Photosynthesis, 76-78 



Pine wood, 135 



Pinnate leaf, 70* 



Plague, 87 



Plant associations, 228*, 229* 



Plant compared to factory, 78 



Plant covering of the earth, *225-233 



Plant food, raw materials, 67, 68, 74, 



78, 203 



Plant food, where made, 69 

 Plant formations, *22 7-229 

 Plants, reproduction of, *270-273, 



*276-280 

 Plants as soil formers, 197, 198*, 



200, 202, 203 



Platinum, 58, 61, 108, 135 

 Pneumatic tire, 1, 6, 10, 49 

 Pneumonia, 87 



Pollution of water supply, *156~164 

 Pond scum, 271, 272* 

 Portages, 149*, 150, 151 

 Potassium, 61 

 Pressure, transmission of in liquids, 



*126-129 



Pressure at faucets, 129 

 Pressure of liquids, *1 18-133 

 Protein manufacture, 242 

 Protoplasm, 73 

 Pulleys, mechanical advantage of, 



176 



Pulleys, use of, *1 73-1 76 

 Pumps, 119, 120*, 121, 122 



Quito, Equador, 105 



Rabbit, overproduction of, 287, 288 



Rabbits, 295, 296 



Ragweed, variation in, 291 



Railways, 147, 148, 151 



Rainfall in United States, 45, 46, 



47* 



Raspberry, 279* 

 Reclamation of swamp lands, 213, 



214 



Refrigeration, 86 

 Refrigerators, 116 

 Reproduction, *2 70-280 

 Reservoirs, for water storage, 160 

 Respiration, 252, 260, 268 

 Rock of earth's crust, *191-199 

 Root hairs, 236*, 237* 

 Root structure, *236~238 

 Running water, work by, *165-169 

 Rural water supply, 162, 163* 



Saliva, 255, 256, 263 



Salmon, overproduction of, 282, 283 



Sand, 200-202 



Sand dune, *221-223 



Sanitary canal, 151, 161, 162 



Saprophytes, 83* 



Saturation, water vapor, 21, 22 



Sault Sainte Marie Canal, 147 



Sea water, 135 



Seasons, *16-20 



Seasons, relation to sun, *16-18 



Sedimentation, *215-223 



Selection, *292-299 



Sewage disposal, *154-164 



Sewers, 160, 161 



Silicon, 61 



Silt, 200-202 



Silver, 61, 135 



Simple substances, 60, 61 



Siphon, 118, 119* 



Sirocco, 38 



Smoke, 14, 15, 63, 79, 80 



Soda water, 65 



Sodium, 61 



Soil, *196-239 



Soil, as water filter, 163 



Soil, kinds of, 200 



Soil, value of, 245 



Soil moisture, distribution of, 206* 



Soil particles, 202, 203, 205* 



Soil water, *205-214 



Soils and man, 226 



Solids, and molecular theory, 53, 



54 



Soot, 63, 79 



Starch, composition of, 68, 74, 75 

 Starch, decomposition of, 68* 

 Starch, digestion of, 248 

 States of matter, 103 

 Steam, *104-108 



Steam engine, 75, 183, 184*, 185-187 

 Steel plants, location of, 148 

 Stegomyia, 100*, 101 

 Stipules, 69 

 Stomata, 72, 73* 

 Storm warnings, 48 

 Struggle for existence, 281-289 

 Submarines, 133, 134 

 Suez Canal, 147 

 Sugar as plant food, 74-77 

 Sulphur, 61, 108, 243 

 Summer residences and climate, 146 

 Sun, altitude of, *16-18 

 Sunflower, 72 

 Sun's rays, inclination of, 17*, 18* 



