430 



INDEX 



Sirius 203 



Skeleton, and muscles . . . 368 



human 369 



Skin, a protective covering 359-360 



care of 362-384,363 



dermis 361 



epidermis 361 



need for cleanliness . . 366-367 



oil glands 361 



regulates body temperature 364 

 use of cosmetics . . . 363-364 



uses 359-365 



sweat glands 360 



Sleep, value of 389 



Slugs 274 



Smoking, effects of ... 395, 396 



Snails 274 



Soap, value of 91 



Soil, acid 242-243 



alkaline 242 



differences in .... 236-237 

 effect of cultivatioh on . 239-240 



how formed 228-235 



kinds of 237 



water in 237, 238 



water film in 238 



Solution of limestone . . 230, 231 



Sow bug 276 



Spectroscope 194 



Sperm nucleus 263-264 



Spider 276 



Spoiling of foods 333 



Sprinters 385 



Spruce 271 



Stamens 262, 263 



Star colors 193 



magnitudes 193 



maps . . . 201,202,204,205 

 Stars, why do they rise and set 



198-199 



Starfish 297,299 



Sterilization, value of ... 340 



Stigma 262,264 



Stimuli, responses to .... 250 



what are they 256 



Stomata 261 



Story test, use of 10 



Stratosphere flight . . . 44,46 



Stream, mountain 214 



Suffocation, first aid .... 404 



Sulphur 218 



Sunfish nest 382 



Sunstroke, first aid .... 404 

 Superstitions, common ... 8, 9 



Survey of yard 270 



Sweat glands, structure . . . 360 

 use of 360 



Table giving ages of fossils . . 225 

 Tables, food values . . . 328-329 



Teeth, care of 379, 381 



Temperature, and microorgan- 

 isms 339 



freezing and boiling . . . 113 



how measured 112 



kindling 105, 106 



of stars 194 



Tests, carbon dioxide ... 50 



for fibers 118-119 



Thermometers 1 12, 113 



Thermos bottle 344 



Tidal pools 297 



Tinder box, use of ... 107-108 



Tire pump 63 



Tissues, examples .... 357-358 



Toad 275 



eggs of 283 



Tobacco, cause of injury . . 396 



Torricelli "... 55 



Traffic squads 402 



Training, and the human ma- 

 chine 389 



Translucent 135 



Transparent 135 



Tree, growth of 292 



Tree of life 298,299 



Trees, rings of growth . . . 292 

 Turtles 283, 284, 285 



Uncas 3,5,389 



Underclothes, porous best . . 365 



uses of 365-366 



weave of 365 



Unconscious activities . . 386, 387 



Vacuum, how made .... 61 

 uses of . . . . 61, 62, 63, 64, 65 



Vaporization 84 



Varied diet, importance of . 314-315 



necessity for 331 



Veins 383 



Vitamins 318, 319, 320 



Volta . 166 



Water, a regulative food 



a solvent 



amount in living things 



boiling of 



composition of ... 



cycle 



distillation .... 

 electrolysis of ... 

 life in . . ... 



pure . . . 

 purification of 



. 321 

 89,90 

 . 92 

 . 114 

 . 82 

 85,86 

 . 84 

 82-83 

 94-96 

 83-84 

 84 



