654 



Index 



earache, 176 



earth, 150, 151, 623, (149) 

 a magnet, 195, 200 

 and moon, 151-155 

 axis of, 132, 156, 159, 162 

 orbit, 150, 151-152 

 revolution of, 119, 132, 134, 151- 



153, 156, (149, 152) 

 rotation of, 119, 132, 133, 134, 



156, 159, 574 

 size of, 151, 157 



earthworms and soil, 301, 564 

 eating, habits of, 354, 409-4 1 

 echoes, 177, 623 

 eclipse, solar, 151, 157, 158, 623, 



640, (158) 



economic importance, 

 of animals, 538-541 

 of bacteria, 444 

 of forests, 514-516, 520, 523 

 of leaves, 499, 501 

 of plants, 494, 527-532 

 of seeds, 512 



economy in foods, 372-373 

 Edison, Thomas A., 232, 567-568, 



575, (568) 



effort, 243, 244-248, 623, (246) 

 Ehrlich, P., 576 

 Einstein, Albert, 572-573, 576, 



(573) 



elasticity, 15 

 electric, 



attraction and repulsion, 203, 



205 



battery, 209-210, 236, 265, 276 

 bell, 217-218, (218) 

 bulbs, 192-193, 231-232, 573, 593, 



(232) 



cars, 18, 226, 266 

 cell, 208-211, 582-584, 585, 586, 



587, 588-589, 623, 635, (210) 

 charging, 204, 205, 206, 208-211 

 circuit, 208, 217, 232, 236, 266, 



583, 619 



conductors, 205, 207, 230 

 current, 18, 192, 203, 206, 208, 209- 

 211, 219-226, 229, 231-233, 235, 

 237, 263, 266, 560, 583, 585, 587, 

 589, 590, 596 



alternating, 223, 224, 266, 615 

 direct, 224, 622 

 induced, 216, 223, 560, (628) 



electric Cont'd 



units of measurement, 211- 



212, 236 

 energy, 16, 18, 67, 68, 74, 203, 208, 



209, 224 



furnace, 595-596 

 fuses, 232-233, 626 

 generator, 224, 265, 626, (74, 224) 

 heating devices, 231, 595-596 

 insulators, 205 

 light, 191, 192, 568 

 arc, 192, 231-232 

 incandescent, 192-193, 232, 573, 



593, 628, (232) 



locomotive, 266-267, (17, 267) 

 measurements, 211-212 

 motor, 216, 225, 266, 273, 276, 588, 



595, 603, 623 

 non-conductors, 205 

 power, 18, 225 

 power plant, 18, 67, 68, 210, 224, 



225, (74, 224) 

 refrigeration, 62, 229 

 resistance, 212, 225, 231-232, 623 

 shock, 343 

 transformer, 225, 234, 235-237, 



(225, 234, 235) 



electrical charges, law of, 205, 630 

 electricity, 82, 136, 203-214, 215, 623, 



(207) 



current, 203, 208, 215, 585 

 kinds of, 204, 206, 208 

 nature of, 203 

 properties of, 203 

 source of, 18, 67, 76, 203, 210, 550 

 static, 203-204, 641 

 unit measures of, 211-212 

 uses of, 62, 63, 203, 215, 226, 229- 

 239, 552-553, 582-594, 595-596, 

 (17, 267) 



electrification, 204, 623 

 electrode, 45, 589, 623 

 electrolysis, 23, 45, 299, 623, (46) 

 electromagnets, 215-228, 266, 560, 



623, (276, 218) 



electromotive force, 212, 623 

 electrons, 204, 207, 208, 572, 583, 623 

 electron theory, 207-208, 623 

 electroplating, 229-230, 623, (230) 

 electroscope, 205, 623, (205) 

 electrotyping, 229-231, 623 

 elements, 23, 28-30, 90, 623 



