618 



Index 



Rabies, 590 



Radiant energy, 106 if., Ill 



Radiation, 103, 106 ff., 110 



Railroads, 253, 266 ff., 276, 316 ff. 



Rain, 50 ff., 197 



Rainfall, distribution of, 51, 196 



and " lows," 28 



Recessive characters, 507 ff., 514 

 Reciprocating engine, 289 ff., 309 ff., 



365 ff. 

 Refrigeration, 147 ff. 



substances used in, 156 



temperatures of, 152 

 Refrigerator, 147 ff. 

 Regenerative braking, 319 

 Relative density, 97 ff., 342 ff., 351 



densities, table of, 343 



humidity, 46 ff., 54, 103 

 Reproductive organs of flower, 484 ff., 



494 



Reservoirs, 218 ff. 

 Resolution of forces, 353 ff., 359 ff. 

 Respiration, 133, 520 

 Rigidity, 432, 450 

 Ringworm, 554 

 Roads, 264 ff., 278 

 Roquefort cheese, 553 

 Root hairs, 462 ff. 

 Roots, 461, 470, 515, 520 



Sand filter, 208, 220 ff. 



Saccharin, 164 



Saltpeter, 74 ff., 585 



Sand, 407, 423, 424 ff., 456 



Sandrock, 406 ff., 411, 415 



Saprophytes, 552, 557, 573 



Saturation of air, 43 ff., 48 ff., 305 ff. 



Scarlet fever, 588 ff. 



Scheele, 70, 74, 77 



Scientific method, steps in, 530 ff. 



Screw propeller, 363 ff. 



Secondary cell, electric, 333 ff. 



Sedimentary rocks, 407, 410, 413 



Sedimentation, 219, 457 



Seed, selection of, 493, 502 



Seedlings, 498, 502 



Selection, artificial, 479, 480 



natural, 477 ff. 

 Sepals, 483 ff., 494 

 Septic tank, 214 ff., 218 

 Serum, 532, 591, 606 ff. 

 Sewage, as disease carrier, 210 



Sewage, bacteria in, 215 ff. 



disposal, municipal, 211, 212, 218 



rural, 213 

 Shale, 408, 413 ff., 419 ff. 

 Silica, 424 ff., 439, 442. 444 

 Silicon, 424 ff., 433, 441, 442 ff 

 Silt, 456, 474 

 Silver, 168 

 Simoom, 34, 41 

 Slag, 439, 443 ff., 449, 451 

 Slaked lime, 417 ff., 426 

 Slate, 407 ff., 411, 415 

 Smallpox, 532, 591, 604 ff. 

 Smoke, 125 ff., 138 

 Snow, 52, 55 

 Soil, aeration, agents of, 470 ff., 475 



air, 469 ff., 475 



and plants, 454 ff., 414 



classification of, 456 ff. 



composition of, 455 ff. 



formation of, 454 ff. 



humus in, 455, 459, 474 



temperature, 472 ff. 



water, amount of, 458 ff., 465, 474 

 character of, 459 ff., 474 

 movement of, 466 ff., 474 

 Solar motor, 67 

 Soo canal, 385 ff., 388 

 Soot, 125 ff., 138 

 Spectrum, 180 ff., 184 

 Spirilla, 577 



Spontaneous combustion, 80 

 Sporangia, 550 

 Spores, 550, 555, 557, 563, 565, 568, 



580 ff. 



Sporoblasts, 527 

 Sporozoites, 527 ff. 

 Sports, 496 ff., 503 

 Springs, 196, 198 

 Stability, 344, 346, 351, 398, 401 

 Stalactites, 411 

 Stalagmites, 411 

 Stamens, 484, 494 

 Staminate flower, 487, 494 

 Standpipe, 229 



Starch, 516 ff., 520 ff., 567, 569 

 Steam, 297 ff., 305 ff., 315, 364 ff. 



engine, operation of, 293 ff., 310 

 ff., 364 ff. 



generation of, 306 ff. 



heating, 101, 306 



turbine, 312, 364, 369 



