Index 



669 



Ships, 270-276, 548, 590, 603, 605, 



607-508, (271, 272, 274, 275) 

 shock, 343, 479, 639 

 shooting stars, 150 

 short circuit, 232 

 siderial system, 148, 161-165, 639 

 sight, 187-188, 330, 639 



aids, 188, 189, 190 



handicaps, 188-190 

 silica, 293-294, 302, 639 

 silicon, 29, 30 

 silver, 30, 205, 229-230, 297 

 simple cell, 209 

 simple machines, 243-250 

 siphon, 40-41, 639, (41) 

 skeleton, 330, 331, 639, (331) 

 skin, 417, 425-426, 455, 640, (426) 



hygiene of, 427 

 slag, 297-298, 640 

 sleep, 435, 452 

 sleeping sickness, 324, 454 

 sleet, 121, 640 

 small intestine, 398, 402-403, 404, 



405, 421, (401) 

 smallpox, 456, 552, 563 

 smell, 330 



smelting, 297, 640, (298) 

 smoke, 85, 91, 104, 106, 131 

 smoking of foods, 445, 447 

 snow, 121, 122, 640 

 soaps, 62, 63, 640 

 sodium, 30 



softening of water, 62 

 soil, 290-309, 516, 640 



air in, 34, 301 



and man, 290, 302, 304 



animals and, 301, 564 



bacteria, 301, 443-444, 529 



cultivation of, 304, 305-307, 493, 

 621 



erosion, 49, 50, 298-299, 306, 514, 

 515, 624, (50, 294, 299) 



exhaustion, 306, 640 



fertility of, 306-307 



formation of, 290, 298, 300-301, 

 516 



kinds of, 301, 302 



life in, 301 



origin, 298 



uses of, 302-304 

 solar, 



day, 159, 640 



solar Cont'd 



eclipse, 151, 157, 158, 623, 640, 

 (158) 



energy (see sun) 



system, 148-155, 640, (149) 



time, 159, 640 

 solid, 14, 82, 88, 640 

 solution, 30, 31, 640 

 solvent, 31, 49, 51, 640 

 soot, 91, 191 

 sound, 170-179, 640 



adaptation of ear to, 170, 

 176 



cause of, 170, 172, 173 



denned, 170 



hygiene of ear, 176-177 



importance of, 170 



intensity of, 172, 177, 629 



production of, 170, 172-175, 584- 

 585 



reflection of, 177-178 



speed of, 171-172 



transmission of, 170-172, 177, 

 221-222 



waves, 170, 173, 176, 177, 221- 



222, 235-237, 585 

 sounder, telegraph, 219, 220, 221, 



640, (220) 



sound strip, 585, (584) 

 spark plug, 263, 265 

 special property, 14, 640 

 spectroscope, 151, 640 

 spectrum, 186, 640 

 speed, 



of light, 102, 165, 181, 185, 236, 

 571 



of sound, 171-172 

 spinal column, 330, 434 

 spinal cord, 431-434, 640 

 spiracles, 537, 640 

 spleen, 401, 417, 420, 423, 640, (401, 



420) 



sponges, 444, 543 

 spontaneous combustion, 85, 96, 



640 



spores, 440-441, 518, 542, 640 

 sprains, 481, 641 

 spring, 56, 641 



mineral, 56-57 

 stability, 276, 641 



standard time, 159-160, 641, (160) 

 standpipes, 53 



