INDEX 



321 



Railroads, early history of, 298 



Rainbow, 106 



Rain, cause of, 35 ; and climate, 54 



Rain cycle, diagram of, 34 



Rain gauge, 46 



Range, coal, 132 



Rapid oxidation, 24 



Rats, as disease carriers, 224 



Rayon, 143 



Receiver, telephone, 272, 274 



Reclamation of land, 211 



Red corpuscles, 95 



Reflecting telescope, 116 



Reflection, 105 



Refracting telescope, 116 



Refraction, law of, 105 



Refrigeration, as a method of preserving 

 food, 90s an d a ! r conditioning, 135 



Refrigerator, electric, 31 



Relative humidity, 29, 31; table of, 30; 

 measurement of, 31 ; correct percentage 

 for home, 31 ; and climate, 54 



Relay telegraph, 269 



Removal of stains, 144 



Reproduction, of bacteria, 217 ; of house 

 fly, 221-222; of mosquito, 221, 223; of 

 flower, 229, 230, 231 ; of one-celled ani- 

 mals, 229 ; of frogs, 229, 231 ; of higher 

 plants and animals, 230-231 ; fertiliza- 

 tion and, 231 ; relation of pollination to, 

 231 ; relation of seeds to, 231 



Residual soil, 208 



Resistance, 253 ; and Ohm's law, 261 



Respiration, 21 



Retina, 113 



Rickets, 82 



Roads, 293 



Roasting, 88 



Rocket, 299 



Rocks, 198 



Roemer, 104 



Roller bearings, 149 



Romans early methods of communication 

 of, 265 



Roots, and photosynthesis, 78 



Rotation of crops, 213 



Rotor, 165 



Roughage in diet, 84 



Rozicr, 309 



Rudder, 308 



Rules, for healthful eating, 84; for care 

 of storage battery, 244 



Running water, and erosion, 203 



Rural water supply, 63 



Rusting, 24 



Rust, removing stains of, 144 



St. Louis motor, 249 



St. Louis water supply system, 65 



Saliva, 92, 93 



Salting, as a method of food preservation, 



89 



Sand, 209 



Santos-Dumont, 312 

 Satellite, 172 

 Saturation, 29 



Saturn, as a planet, 182; views of, 183 

 Savannah, 304 

 Scales, types of, 150-151 

 Sea breezes, cause of, 41 

 Seasons, cause of, 191 

 Secondary circuit, 277 

 Secondary winding of transformer, 252 

 Sedimentary rock, 198-199 

 Sedimentation, 59 

 Seeds, how formed, 231 ; germination and 



food supply of, 79 

 Seismograph, 206 

 Selection, in improvement of plants and 



animals, 236, 237 



Semi-direct lighting, 110 



Sepals, 231 



Septic tank, 74 



Sewage disposal, and water supply, 73 ; 

 methods of, 73, 74 



Sex cells, 230 



Shale, 199 



Shiaparelli, 182 



Ships, 306 



Short circuit, 253 



Silk, 143 



Silt, 209 



Sinking bodies, 303, 304 



Siphon, operation of, 7, 8, 10 ; in house 

 plumbing, 73 



Sleeping sickness, 219 



Smallpox, 218 



Snow, 36 



Soap, as a water softener, 61 



Soil, fertility and food supply, 79; experi- 

 ment, 207; formation and transporta- 

 tion of, 208; residual, 208; kinds of, 

 209; irrigation of, 211; drainage of, 

 211; maintaining fertility of, 211 



Solar cooker, 168 



Solar eclipse, 190 



Solar system, defined, 179; heavenly bodies 

 in, 180 



Solstice, 191 



Solution, 57 



Solvent, 57 



Sound movies, 286 



Sound, production of, 16; transmission of, 

 16, 17 ; velocity of, 17 ; in music, 18 



Sounder, telegraph, 268 



Spectroscope, 177; use of in studying stars, 

 181 



Spectrum, of sunlight, 106 



Sperm, 230 



S perry, 306 



Spiral nebulae, 176 



Spirillum, 216 



Spontaneous combustion, 139 



Spore, 87, 217 



Spraying, for insects, 227 



Stability, defined, 302; factors that affect, 

 305 



Stain, removal of, 144 



Standard time, 193 



Standpipe, 72 



Starch, test for, 80 ; effect of cooking on, 

 88 



Star clusters, 176 



Star maps, 171, 172, 173 



Stars, 174, 176. 177 



Static electricity, 240, 241 



Steam, invisible, 30 ; force of, 163 ; energy 

 from, 292 



Steam engine, history of, 164 ; experiment, 

 163, 292 ; and electric generator, 251 



Steam heating system, 132 



Steam turbine, 163 



Steaming, as a method of cooking, 88 



Step-down transformer, 252 



Stephenson, George, 298 



Step-up transformer, 252 



Sterilization, 57 



Stevens and Anderson, 4 



Stigma, 231 



Stopping distances of cars, 153 



Storage battery, 240, 243, 244 



Stormoguide, 45 



Stove, 132 



Stratosphere. 4 



Stratus, 35, 36, 196 



Streamlining, 149, 300 



Strings, vibrating, 19 



Strokes, of gasoline engine, 295 



Style, 231 



Submarines, principle of, 306 ; modern, 307 



Subways, 301 



Suction, 7 



Sugar, 80 



Sulphur dioxide, 24, 32 



Sun, energy from in evaporation, 30; 

 slanting and direct rays of, 54; nature 

 of, 180; size and distance of, 180 



Sunlight, composition of, 106 



Sunshine vitamin, 82 



Sun spots, 179, 180 



Super-sonic sound waves, 19 



Switch, telegraphic, 269 



Tadpole, 231 



Teeth, care of, 94 



Telegraph code, 268 



Telegraph, experiment, 266 ; sending mes- 

 sages by, 267, 269 ; early history of, 267 ; 

 homemade, 267; invention of, 268; 

 parts of simple, 268 



Telephone, experiment, 272 ; early history 

 of, 272; operation of, 275; trans- 

 oceanic, 286 



Telescope, how to make a simple, 111 ; re- 

 fracting, 116, 177; reflecting, 116, 177; 

 Yerkes, 117; Lick, 177; Mount Wilson, 

 178; 200-inch mirror, 178 



Teletypewriter, 270 



Television, 288 



Temperature zones, 52 



Temperature, and food supply, 79; dif- 

 ferentiated from heat, 126; measure- 

 ment of, 127; regulation of the body, 

 141 ; effect of changes on rocks, 202 ; 

 soil, 211 ; and bacteria, 217 



Temporary hardness, 58 



Temporary stars, 177 



Terminal, 240 



Tetanus, 219 



Textile fibers, identification of, 141 ; laun- 

 dering of, 141 ; stain removal from, 

 141 ; sources of, 142 



Thales. 241 



Thermometer, in relative humidity, 31 ; 

 construction and operation of, 43, 127 ; 

 in weather forecasting, 44; maximum- 

 minimum, 45; early types of, 127 



Thermos bottle, 131 



Thermostat, 135 



Thorium, 101 



Thunderstorm, cause of, 48 



Tides, spring, 186, 190; neap, 186, 190; 

 causes of, 189 ; as agents of erosion, 204 



Time, and longitude, 192; sun, 192; stand- 

 ard, 193 ; calculation of, 193 



Tissues, relation of cells to, 230; relation 

 of organs to, 230 



Toilet, dry earth, 73 



Tombaugh, C. W., 183 



Tom Thumb, 299 



Tones, musical, 18 



Tornado, nature of. 48 



Torricelli, Evangelista, 5 



Torrid zones, 51, 52 



Total eclipse, 190 



Tourniquet, 95 



Toxins, 218 



Trade winds, 41 



Trains, streamlined, 300; electric. 301 



Transformation of energy, 120 



Transformer, electric, 251 



Translucence, 103 



Transmission, of automobile, 297 



Transparent bodies, 105 



Transportation, by land, 293 ; by automo- 

 bile 294-298; by rail, 298-301; by bus, 

 301 ; by water, 303-307. 



Transported soils, 208 



Traps for insect pests. 227 



Trevithick, Richard, 298 



Trolley cars, history of, 301 



Tropic of Cancer, 52, 191 



