INDEX 



403 



Sal soda, 161 



Saliva, 357, 358 



Salmon, overproduction of, 376 



Sand, 288, 289 



Sand dunes, 310* 



Sanitary canal, 168, 169 



Saprophytes, 91, 92* 



Satellites of Jupiter, 257 



Saturation, and the dew point, 26; 

 water vapor, 23 



Saturn, 253, 258*-259 



Sault Sainte Marie Canal, 154 



Scorpio, 278 



Sea breezes, 143, 144 



Sea water, 140 



Seasons, *32-37 



Sedimentation, *304-311 



Sediments in water, 161 



Seed plants, reproduction of, 369-370 



Seedling, 372 



Selection, natural and artificial, 

 387-393 



Series circuit, 202 



Sewage disposal, *159-172 



Sewage treatment, 169 



Silicon, 69 



Silt, 289, 290, 307-308 



Silver, 69, 140, 268 



Simple substances, 68 



Siphon, 128-129* 



Sirius, 273 



Sirocco, 47 



Smoke, 19, 71, 88 



Soda water, 72 



Sodium, 69 



Soil, bacteria of, 313-314 ; deposited 

 by erosion, 308*-309 ; fertility of, 

 288-293 ; kinds of, 288 ; life in, 

 312-314 ; significance of, 286-287 ; 

 structure of, 288-293 ; value of, 

 293 



Soil particles, 290-291 



Soil temperature, 295-296 



Soil water, *294-303 ; affected by 

 tillage, 296-297 ; artificial drain- 

 age, 299 : natural drainage, 297- 

 298 



Soils and man, 314 



" Solar engines," 193 



Solids and molecular theory, 62 



Soot, 71 



Spark plug, 214 



Spectroscope, 267-268 



Spiral nebula, 270* 



Spores, 89 



Stamen, 371* 



Starch, composition of, 77 ; decom- 

 position of, 77* ; digestion of, 331 

 in the leaf, 84 



Stars, magnitudes of, 269 ; nature 

 and distance of, 268-269 ; visible 

 in April, May, and June, 276 ; vis- 

 ible in January, February, and 

 March, 273-275 ; visible in July, 

 August, and September, 276-278 ; 

 visible in October, November, and 

 December, 271-273 



Steam, 114, 116, 117 



Steam engine, essentials of, 187, 189* 



Steel plants, location of, 154 



Stegomyia, 111*, 112 



Sterilization, 94, 95 



Stomata, 79-80 



Storm warnings, 56 



Stoves, 17*, 18* 



Struggle for existence, 374-382, 378* 



Submarines, 138 



Suez Canal, 154 



Sugar, composition of, 77 ; in the 

 leaf, 84 



Sulphur, 69, 119, 268, 330 



Sun, *2l>4-278 ; constitution of, 267 ; 

 distance and size of, 264-265 ; 

 storms on, 266 



Sunflower, 80 



Sun's heat, source of, 266 



Sun's rays, inclination of, 35 



Sun's surface, explosions on, 267* 



Swamp lands, reclamation of, 303 



Symbols, chemical, 69, 71 



Synthesis, 85 



Tadpole, 367*, 368 



Taurus, 274 



Tea, 345, 351 



Teakettle, 117 



Teeth, 339 



Temperature, of air, 8, 12-20, 32- 

 37; in cyclones, 45; seasonal 

 changes of, 34 ; of soil, 295-296 



Test for living materials, 89 



Texas fever, 112, 385-386 



Thermometers, 14-15*, 121*; used 

 in candy-making, 118 



Thunderstorms, 49, 50 



Tick and cattle fever, 112, 385-386 



Tillage, effect on soil water, 296-297 



Tin, 69, 140, 268 



Tire, pneumatic, 3, 5, 12 



Tornadoes, 44, 60*, 51, 52* 



