None
ABERRATION, 283 Abney, 378 Absolute minimum of electricity, 75 Absolute motion, 283 Absorption, model of, 265, 266, 357 selective, 246 Action at a distance, 360 — 363, 460 Affinity, chemical, I, 76 Agriculture, Electric discharge in, .193 Air, electrification of, 193 Air-battery, 112 Air-gap, effect of, in magnets, 158 Aitken, 435, 436 Alternate contact, discharge by, 56 Alternating current, equation to, 489, 490 resistance to, 98, 489, 490 Alternating energy, 322 Ampere, 91 Ampere's theory of magnetism, 146 —148, 167 Amperian currents, 148 Amplitude of Light-waves, 333 Analogies : see Models Analogue of organ, 249 Analysis of oscillatory discharge, 403 Angle, solid, 486 Animals, Luminous emission of, 476 Anion, 82 Anomalous dispersion, 246 magnetisation, 397 Antimony, 281 Arago experiment. 374 Argument from experience, 359, 360 Artificial lighting, 248 — 251 Astronomical Analogy, 449, 475,, Atmosphere, density of, 372 Atom, of electricity, 75, 418, 421, 442 current in, 147, 148 disintegration of, 433, 447, 448, 473 elasticity of, 368 energy in, 448, 472 infinite properties of, 147 instability of, 473 intensity of attraction, 76 locomotion of, 80 — 85 mass of, 419 mass smaller than, 426 of hydrogen, 444 potential of, 76 radiating, 424 surgings in, 242 ultimate, 411 vibration of, 376 — 378 Atomic aggregates, 323 charge, 72, 74—76 oscillations, 317 potential, 76 projectiles, 468 vibration, 242 vibration, frequency of, 256 — .258 Atomicity, 74 504 INDEX Atoms and molecules, constitution of, 411, 471 Atoms, heat emission by, 473 loading of ether by, 330 of matter, 409 of the Elements, 323, 443 origin of, 475 rays from, 472 Attraction and repulsion, caused by strain in medium, 27 Attraction of atoms, intensity of, 76 Attractions, chemical, 323 Aurora Borealis, 142 B. BECQUEREL, 358, 442^., 464 Beetz, 148 " B" flashes, 102 Belt, Graham, 356, 358 Berkeley, Bishop, 502 Bichat and Blondlot, 407 Bidwell, Shelford, 280, 358 Biot, 13 Bird- cage experiment, 12 Bismuth, 281, 282 effect of magnetism on, 281 wire, 282 Bisulphide of carbon, 335 Blyth, 309 Bode's law, 449 Boltzmann, 309 Bornstein, 283 Boys, V., I4»., 378 Branly, 310 British Association, Montreal, 439 Oxford, 290 Bursting of jar, 401 C. CAPACITY, 28, 29 effect of, on signals, 232 Carey Foster, 278 Carroll, Lewis, 418 Cathode rays, 428 — 431 Cation, 82 Cavendish, 8 experiment, 13, 27, 30, 224, 320, 324 experiment, moral of, 224 laboratory, 434, 435 Cavities in medium, 20, 26, 27 Centrifugal force analogue of magnetic repulsion, 168 — 171 Charge, 25, 27, 31, 142 and varying magnetic field, 143 atomic, 72, 74, 76, 421 by alternate contact, 55 — 56 by induction, 43 — 53 inertia of, 445 internal, 36 ionic, 422 moving, 126 — 128, 141, 203, 282 residual, 37 spurious, 53 surface, 53 Charged air-penetrating wire gauze, ^3 sphere, motion of, 127 Chemical affinity, I, 76 attractions, 323 elasticity, 217 equivalent, 74 fumes, 1 02 Chinaman, 363, 364 Chlorophyll, 312 Clausius, 77 Clerk Maxwell : see Maxwell Clouds and mist, 435, 438, 439 Cobweb analogy, 341 Cog-wheel analogy, 325 Coherer effect, 309, 310 Cohesion, I, 365, 369 Coil imitating magnet, 132 Colour sensation, 258 Combustion, an indirect source of light, 250 Comets' tails, 314, 341 Communication, modes of, 365 — 367 Commutated circuit, resistance of, 488 Concentration by reflexion, 253 Condensation of emanations, 470 of vapour, 435, 437 INDEX 505 Condenser, stratified, 35 — 36 discharge of, 222 — 225 momentum in, 27 Condensers, 32 Conduction, gaseous, 123 — 126 in liquid, 71 — 86 in metals, 67 — 71 of heat, 1 18 surface, 99 Conductivity, magnetic, 154 effect of light on, 283 Conductor, hollow, 100 moving in magnetic field, 199 perfect, 163, 165, 178, 185, 193, 252, 265, 266, 313 radiation encountering, 253, 262, 265 Conductors, effects, 278, 280 function of, loo like cavities, 20, 65 opacity of, 262 — 267,287, 356, 357. Contact action, 460 -force, 109—116 Continuous Medium v. Action at a Distance, 362 Controversies, optical, 288 Convection of heat, water, and elec- tricity, 66, 421 Copper, 281, 307 and revolving magnet, 313 electrolytic obstruction, 139 Copper-disc experiment, 150 Copper-disc, repulsion of, 315 Cord-models, 33 — 55, 81, 114 Corpuscles, 438, 441, 443, 444, 445 Corpuscular theories, 367 Corti's fibres, 258 Critical speed of matter and of electron, 321, 328 Crookes, 307, 314, 427-429, 442, 465, 466 Curie, M., 442^., 464 M. and Mme., 463 Mme., 466 Current, action of, on pole, 133 alternating, 99, 101, 489 Amperian, 148 as moving charge 126, 282 brake analogue of, 193 Current, condition of medium near, 90 density of, 68 distribution of, 188 disturbance not confined to con- ductor, 90 — 96 energy of, 93-97, 449 excited by light, 287—288 exerting mechanical force, 197 extra, 88, 90 — 92, 182, 487 heat of, 69 imitating magnet, 482 in atom, 147 in perfect conductor, 179 in primary circuit, 488 induced, 452 intensity of, 68 induction, 91, 487 lag of, 189 magnetic properties of, 90 — 93 model of, 176 — 189 molecular, 148—153, 165, 166' of discharging Jar, 489 produced by rotating magnet, 145 production of, 203 propelled by side thrust, 92, . 95. 231 rise in secondary circuit, 190 — 194 rotating magnet, 143 starts at surface of wire, 95, 231 stopped by resistance, 147 time taken to start, 95 varying, 180 — 189 viscosity, analogue of, 95 — 97 Currents, action between two, 90 synchronised, 291 transient, 418 Cycle, magnetic, 161 Cyclone, 383 D. D ALTON, 421 D'Arsonval, 236 Darwinian evolution, 436 Decomposition, 76 — 82, 380, 420 Density, elasticity and, 495 magnetic, 321 5o6 INDEX Density, of current, 68 of ether, 181, 200, 216, 319, 324, 326, 329, 335, 340, 372 of ether, Fresnel's hypothesis, 372 Diagrams of Electric and magnetic forces, 302 Diamagnetism, Newentry experi- ment illustrating, 151 Weber's theory of, 148—153 Dielectric, breaking down of, 29, 30 constant : see Specific inductive capacity cord -model of, 34 — 39 stratified, 35—41 strength, 125, 126 Differences between electricity and fluid, 16 Diffraction, 261 Diffusion velocity in cables, 232 Dimension of electric quantities, 494. Direction of vibration, 288 Discharge, by alternate contact, 56, 57 disruptive, 33, 36,42, 125, 201, 202 dissipation of energy from, 225 intermittent, 393, 404 of condenser, three main cases, 221, 393 of condenser, dying out of vibrations, 222, 395 of condenser, theory of, 488 oscillatory, 42, 43, 93, 221 — 225, 387-408 tuning-fork, analogue, 223, 395 wave-length, 239, 488 Dispersion, 245, 246, 316 anomalous, 246 optical, 316 Displacement, 40, 42, 44, 208, 209, 252 Disruptive discharge, 33, 36, 42, 125, 202 Dissipation of energy, 266, 491 by conductor, loi from discharge, 225 Dissociation, 77, 78, 105, 331, 375, 473 Dissymmetry, 118 Disturbances, oscillatory, 16 Dog, modes of calling, 365 Double decomposition, 77, 78 Doubleness of constitution of ether, 214 : see also Dual view of elec- tricity Dragoumis, Dr., 288/2. , 306 Dual view of electricity, 26, 27, 79, 82, 83, 84, 164—166, 214, 380 of ether, 215, 332, 378 Dust, 439 nucleus, 438 Dynamical Theory, 451, 461 E. 5o8 INDEX Empiricism of present modes of getting light, 248 Energy, alternating, 322 classification of, 472 dissipation of, 266, 491 dissipation of, by conductor, 101 in atom, 448, 472 intrinsic, 318 of current, 93—97, 485 of ether, 319, 325, 330 of radiation, 298 of sunlight, 333 oscillating, 301 paths of, 94—97 per cubic millimetre of ether, 330. potential, 410 rotational, 318 transfer of, to distance, 194 — 197 transmission of, 95 — 106 two forms of, 352 Ether, continuity of, 410 decomposition of, 380 dislocation of, 322 dissociation of, 331 effect of E.M.F. on, 332 electrified, 340 energy of, 330 ingredients of, 331 kinetic energy of, 340 massiveness of the, 323, 339 other functions of, 501 positive and negative con- stituents of, 331 possible functions of, 319, 500 psychical function of, 501, 502 solidity of, 319 strains in, 415 stress in, 338 turbulent motion of, 319 zero viscosity of, 320 Ether and electricity, 370, 379, 415 Ether and chemical affinity, I and cohesion, I and gravitation, I, 324, 381, 501 and matter, 380 — 386, 455 constants of, 226 — 237 constitution of, 216, 322, 33i> 369, 370, 379, 386 Ether, density of, 181, 200, 216, 319, 324, 326, 329, 335, 336, 34p, 372 density of, probable real value, 226, 330 doubleness of constitution, 214 dual view of, 215, 332, 378 effect of matter on, 372 elasticity of, 215, 226, 227, 329,. 37 1 elasticity accounted for, 255, 256 Fitzgerald's model of, 254 fluidity and rigidity of, 16, 17, 214, 319,321, 324, 338 free and bound, 373, 379 free, simple structure of, 245 functions of, 359, 386 incompressibility of, 16, 17, 28 — 31, 224, 324 inertia of, 214, 318, 321, 322, 338> 371 jelly theory of, 19, 370 Maxwell's model, 254 most recent views, 318 motion through, 283 penetrability of, 19 rigidity, probable value, 372, 373 sheared, 322, 331, 379 universal connecting medium, I Ethereal circulation, 326 constants, 318, 329 energy, 319 ripples, seeing by, 2 sense organ, 456 spelling of, 329 waves, 2, 459 Ethereous view of electricity, preface constants, value of, 329 Ethereous, note on the word, 329*5. Evaporation, 436 Everett, 435 Ewing, 154, 155, 159, 162, 163, 274 Extra current, 88, 90 — 92, 182 Eye, an ethereal sense organ, I electric, 258, 293, 297 waves affecting the, 459 INDEX 509 F. FARADAY, 8, 12, 13, 21, 23, 30, 75, 91, 270, 271, 315, 354, 355, 358, 395, 396, 414, 4i6, 419* 420, 424 electro-optic effect, 268 — 285, 354, 355 electro-optic effect, connected with Hall's, 279, 280 electro-optic effect, model of, electro-optic effect, time of, 404 laws of electrolysis, 71 — 86 second law, 75 Faraday's dielectric constant, 321, 329 tube, 340 Favre, 431 Feddersen, 42 Fessenden, 496, 497, 5°2 Film affecting reflexion, 262 Firefly, 311, 476 Fitzgerald, 255, 288;*., 290, 309, 314, 316, 325, 356, 424, 496, 501, 502 receiver, the, 309, 310 Fitzgerald's ether model, 253 — 255 Fizeau experiment, 283, 374, 375^. Fluid incompressible, 16 theories of electricity, 9, 16, 17, 20, 25, 27^ Fluidity and rigidity of ether, 16, 17, 214 Fluids, magnetization of, 159 and solids, 160 Fluorescence, 260 Flywheel, analogue of magnetism, 163, 181, 193 Force, magneto-motive, 153 motion and, 451, 452 sense of, 454 Forces acting on conductors, 197, 198 attractive, 369 repulsive, 369 Foster, 278 Foundations of science, 477 Franklin, 8, n, 25 Free path, 429 Frequencies, oscillation, 240, 241 Frequency of atomic vibration, 256 — 260 Fresnel, 215, 304 Fresnel's ether theory, 372 — 375 Friction, between matter and ether, 213 resistance, 68, 69 Frictional electricity, 213 Fume, deposition of, 193 Fundamental explanation, 318, 386, 412, 451 relations, 495 G. GALILEO, 147 Galvanometer analogy, 15 Gaseous conduction, 123 — 126 Gases and electrolytes, 124, 125 kinetic theory of, 367 Geitel, 442/2. Generation of magnetic field, 204, 205 Glass conductivity, affected by light, 284 Glazebrook, 237 Glow-worm, 250, 311, 459, 476 Gold-thread experiment, 135, 136 Gore's railway, 138 Gramme ring, 205 Gravitation, I, 224, 332, 381, 460, 501 Newton's views on, 381, 465 propagation of, 224 smallness of, 385 theories of, 367, 369, 381 velocity of, 224 Gravity compared with chemical affinity, 76 Green, 9 Gregory detector, 308 Grotthus, 78 Grove, 358 Gyrostat explaining elasticity, 256 Gyrostatic elasticity, 320 inaction of magnet, 88 — 90, 5io INDEX H HALL, 271, 278, 281 effect, 268, 278 effect in insulators, 276 effect, thermo-electric view of, 280—283 Hallwachs, 284 Heat and radiation, 66 emission by atoms, 473 irreversible, 115, 116 modes of transfer, 66, 7 1 nerves, 458 produced by current, 69 produced by magnetization, 161 radiant, I reversible, 115, 116 what is, 346 Heaviside, 153, 233, 325, 391, 399"- , 417 Heavy glass, 354 Hele Shaw, 104 Helium, 468 Helmholtz, 77, 108, 134, 398, 418, 425, preface specific attraction for elec- tricity, 1 08 Henry, Joseph, 396 — 398 Hertz, 229, 286, 287, 290, 298, 301, 306—308, 395, 396, 425 experiments, 286 — 290 et seq., 424, 428 Hewitt, Cooper, 307 Hicks, W. M., 255 Hittorf, 427 Hollow conductor, 100 vessel, experiments in, 4, 12, 224 Holtz machine, 70, 85 Hooke's law in electrical case, 220 Hopkinson, 246 Horse and cart, 364 Hot glass conducting, 284 Howard, 28872. Hughes, 97, 189 Hull : see Nicholls. Hydraulic analogies, breakdown of, 94 models, 53 — 59 Hydrodynamical theory, 412 Hydrogen, atom of, 444 Hydrogen, speed of, 37, 86 Hysteresis, 160, 162, 274, 275 I. ICE pail experiment, 12 23, 30 moral of, 224 Illustrations, 22, 24, 25, 34, 35, 39, 41, 43, 44, 45, 48, 52, 54, 55, 58, 59, 81, 103, 104, 114, 132, 135— 141, 143, 144, 151, 154, 167, 169 —171, 173— 175, 178, 183—185, 188, 191, 199, 201,205, 254, 271, 277, 279, 291, 293—299, 302, 357, 389 Immobility, rigidity, and shear, 319 Impedance, 321, 322, 490, 491 and resistance, 490 Impetus : see Momentum Incompressibility, 320 of electricity, 28 — 31 of ether, 16, 17, 224, 324 Incompressible fluid, ocean of, 18 Index of refraction andsp. ind. cap., 243—247 Induced charge, 31, 43 — 61 current, 190 — 194 E.M.F., 487, 490 Inductance, 483, 484 Induction coil theory, 492 cord model of, 43 illustrated by strained medium, 28 magnetic, 154, 481, 486 mutual, 483 self : see Self-induction Inductive retardation, 28 Inductivity, 36 Inertia, electromagnetic, 391 of charge, 445 of electricity, 15, 43, 87, 88, 92, 103—105, 163—165, 176, 182, 218, 318, 416 of electron, 327, 445 of ether, 215, 318, 321, 322, 338, 445 of iron, 233 of radiation source, 425 Insulating medium conveys signals, 230 INDEX Insulators, Hall effect in, 276 transparency of, 261 — 264, 356 Intensity of current, 68 Interference, 266, 267, 306, 335 bands, 267 Internal charge, 40 Interstellar ether, 318, 450 et seq.> preface Interstices between particles, 341 Intrinsic energy of ether, 328 lonisation, 124 Ions, 323, 419 speed of, 84, 85 Iron, effect of, 101, 198 — 200 ether density in, 20, 200 function of, in retarding signals, 189, 232 function of, 153, 154 magnetic effect of, 153, 188, 198, 199. 392 permeability of, 154, 155, 181, 200 saturation of, 155 wire, properties of, 95, 96, 99 Irreversible heat, 115, 116 Isolated metals, potential of, 113 j. JAR, overflow of, 401 Jelly, analogue of ether, 17, 1 8, 60 Joule, 70, 115, 490 K. KALEIDOPHONE, Wheatstone's, 427 Keeper, use of, 158 Kelvin, Lord, 17, 42, in, 113, 118, 119, 227, 255, 256, 313, 320, 325,355* 39^406, 412, 418, 419, 435, 439 effect, 118 form of Volta effect, 113 theory of elasticity, 17, 256, 320 theory of matter, 385, 386 Kepler, 354 Kerr, 274, 356 electro-optic effect, 262 — 285 Kinds of wave propagation, 224 Kinetic energy, 318, 340, 410, 448 of ether, 339, 340 theories, 365 — 368 Kinetic rigidity, 320 Kohlrausch, 85 Kundt and Rontgen, 356 LAG, initial quarter-period, 300 Lamb, Prof. Horace, 257 Langley, 311, 378 Larmor, 325, 335, 415, 422, 424, 448, 477 Lateral propulsion of currents, 93, 97, 231 Lectures on Radium, 463 et seq. Lenard, 282, 307, 428 rays, 438, 463 Leyden jar, 32—33, 42, 93, 100, 193, 307, 387—408, 488 bursting, 401, 402 discharge, rotating plane of polarization, 404 — 408 emitting waves, 225 frequency, 140 hydraulic model of, 53 — 6 1 insulated, 55 method of determining speed of pulses in wires, 235 syntonic, 291 theory, 488 wave-length, 223 Life and Mind, 452 Light, affecting conductivity, 283 and electric radiation velocities compared in matter, 243 and electricity, 289, 307, 352 as travelling momentum, 333 common indirect mode of obtaining, 249 energy of, 266 exciting currents, 286 manufacture of, 248 — 251, 317 modern theory of, 289 momentum of, 332 phenomena of, I present modes of obtaining, 248 5I2 INDEX Light, pressure of, 314, 315, 316, 332, 333 propagation of, 371 radiation, 16 reflected at surface, amount of, 261, 262 tangential force of, 316 transmission of, 371, 457 velocity of, 243—247, 328, 335, . 373, 374 violet, on spark-length, 284 waves, length of, 239 — 242 what is, 349 Lighting, artificial, 248 — 251 Lightning conductor, 99, 101, 102 Globe, 380 Lines of force, 21 — 26, 415 between two discs, 22 like elastic threads, 21 like rays of light, 24 magnetic, 166 — 171 Liquid rotated by magnet, 139 spiral jet of, 140 theory of electricity, 14 Locomotion, 322 of electricity, 65, 126 Lodge, 89, 118, 142, 152, 157, 208, 236, 237, 288;*., 314 Lorentz, 424, 425 Loschmidt, 419 Luminescence, 311 Luminous frequencies, 293 nodes and loops, 401 waves, 242 M. MACALISTER, DONALD, experiment by, 13 McCullagh, 305 McCullagh's ether theory, 381 Magic, 362 Magnet, and gold-thread, 136 and moving charge, 141 gyrostatic inaction of, 88 — 90, 164 imitated by coil, 132, 483 in form of ring, 154, 158, 205 — 208 rotated by current, 143 Magnet, rotating, producing cur- rent, 144 rotating liquid, 138 Magnetic and electrostatic fields superposed, 200 — 201 attraction and repulsion, 168 — 171 circuit, 153, 482 circulation, speed of, 336 conductivity, 154 cycle, 161 density, 321 field, generation of, 204, 205 field, models of, 172 — 188 field, near an electron, 328 field, producing electrostatic effect, 143, 204, 207 field, spreading, 179 field, velocity in, 325 flow, 333, 335 flux, 481 function of iron, 153, 188, 198, 199, 392 induction, 154, 445, 481, 486 line offeree, 166 — 171, 282 medium, stress in, 167 — 170 moment, 481 moment of circuit, 445 permeability, 153—156, 181, 321, 482 permeability, probable real value, 227 properties of electric currents, 417. properties of disruptive dis- charge, 202 quality of iron, 101 reluctance, 153, 482 resistance, 153 rotation experiments, 135 — 145 screen, 193 storms, 241 substances, opacity of, 270 whirls, 167 — 171 Magnetism, Ampere's theory of, 146 — 148, 167 flywheel, analogue of, 163, 181, 193 permanent, 152, 156, 157, 160 permanent, universal, 274 INDEX 5*3 Magnetism, phenomena of, I sub-permanent, 158 Magnetization, 148, 149, 156 heat produced by, 161 mechanism of the act of, 162 of fluids, 159 of steel, 160 Magneto-electricity, 486 -motive force, 153, 482 Maintenance of radiation, 241, 308 of vibrations, 317 Manganese steel, 155 Manufacture of light, 248—251, 317 Marconi. 311 Marionette, 362 Material inertia, 417 substratum, 446 Matter, an inference, 454 and electricity, unification of, 447 and ether, 338, 380 — 386 and motion, 410 atoms of, 409 electrical theory of, 477 in fourth state, 429 mass of, 339 permanence of, 475 vortex theory of, 384 — 386 Maxwell, 8, 9, 13/2., 88, 89, 163, 255, 289, 305, 312, 314, 315, 3i6, 332, 353, 355, 356, 395, 398, 419, 424, 425, 442, 500, preface Maxwell's ether model, 254 experiment on Fresnel's theory, 375 momentum experiment, 88, 89 theory of light, 289 Mechanical analogies : see Models Mechanism of radiation, 251 — 267 Media of communication, 365 — 367 Medium, strain of, 220 Melde's experiment analogue, 236 Mental imagery, advantage of, 78 Metallic condition, 67 — 71 cord-models, 33 — 55 reflexion, 253 Metals, isolated, 113 Metaphysical arguments, validity of, 359, 36o Methods of communication, 365 — 367 Michelson, 283, 442/2. recent experiments of, 375^. Milky- way analogy, 341 Milton, 329 Minchin, 358 Mist, 435, 437, 440 Model, cord, 33 — 55, 81, 114 ethers, 254 hydraulic, 53—59 Maxwell's, 255 of absorption, 266, 357 of electrolyte, 79 of magnetic field, 172 — 188 of opacity, 356 of radiation, 251 of reflexion, 261 — 267, 357 of self-induction, 182 — 189 Modern electron theory, 255 Modern views of matter, 409 et seq. , 423 Molecular currents, 148 — 153, 165, 1 66 Molecule, 411 Momentum in condenser, 27 of electricity, 88, 89, 103 — 105, 163, 165, of light, 332 Motion, absolute, 283 and force, 451, 452 matter and, 410 of sphere, 324, 325 perpetual, 134 psychical interpretation of, 502 sense of, 453 Moving charge, 126, 128, 141, 203, 282 charge and magnet, 143 Musical sparks, 402 — 406 Mutual forces, action of, 369 Mutual induction, 483 Myers, 292 NATURE, Laws of, 477 Nature, 152, 291, 293, 301, 305, 306, 317, 439 Nebula Theory, 449 L L INDEX Negative electricity, existence of: see Dual view of electricity Newton's guesses on the ether, 497—500 laws of motion, 422 queries, 381, 496 rings, 305 second law, 417 Nicholls and Hull, 315 Niven, 257 Nodes, 306 Nucleus, 437 O. OCEAN of incompressible fluid, 18 Ohm's law, 69, 71, 192, 220, 490 Opacity, 312-314 and wave-lengths, 312 model of, 356 of conductors, 262 — 267, 287, 356, 357 of magnetic substances, 270 Optical controversies, 288 Optics and electricity, 289 Organ analogue, 249, 408 Oscillation in conductor, 257 — 261 frequencies, 240, 241 in earth and sun, 240 period, 223, 390 et seq. Oscillators of Hertz, 286, 293 Oscillatory discharge, 42, 43, 93, 221—225, 387, 408 analyzed by mirror, 403 disturbances, 16 Outstanding problems, 282 Overflow of jar, 401 Oxford, 290 P. PATHS of energy, 94 — 97 Peltier effect, 115, 116, 119 Penetrability of ether, 19 Perfect conductor, 163, 165, 179, 193, 252, 265, 266, 313 properties, 147 solid, 320 Period of oscillation, 223, 390 et seq. Permanent magnetism, 152, 156, 157, 160 magnetism, universal, 274 Permeability, 153 — 156, 181, 482 not constant, 274 real value of, 227 Perpetual motion, 134 Phenomena of light, I electricity, I magnetism, I Philosophical Magazine, 335, 338, 472 Phosphorescence, 242, 250, 260, 317, Photophone, 358 Physiology, 459 Pictet, M., 313 Pitch, index of refraction of, 288 prism, 288 Pitchblende, 466 Plane of polarization rotated, model of, 355 Polarization, 304, 491 electrolytic, 109 of electric radiation, 287, 304 Pole, acted on by current, 133 — 134 Potential, 27 energy, 410 of atoms, 76 of isolated metals, 113 of pole on circuit, 486 uniform in conductors, 20 Pouillet's thermal measurements, 333 Poyntmg, 94, 95—97, 105, 223, 233, 30i, 333> 334, 339 Pressure and dielectric-strength, 125, 126, 314 Prism, pitch, 288 Problems outstanding, 282 Projectile method of communica- tion, 365—367 Prout, 443 Progress, recent (1892), 290 — 317 Propagation of light, 371 of sound, 171, 371 Pyro-electricity, 121 Q- QUANTIVALENCE, 74 Questions not yet answered, 414 INDEX 515 Questions to be answered, 413 Quincke, 273 R. RADIANT heat, i Radiation, detection of, 306, 309, 456 and heat, 66 electric, 425 electric speed of, 226 — 247 emission of, 330 encountering conductor, 253, 262 — 267 energy, 298 exciting currents, 287, 288 focussing of, 296 loss of energy, 241 maintenance of, 241 mechanism of, 251 — 267 polarized, 287 process of, 299 et seq. production of, 258, 286 proportional to square of acceleration, 331 reflected, 285, 305 refracted, 286 speed, modes of observing, 222 — 247 waste, 249, 250 wave-length of, 489 Radioactivity, 447, 465, 467, 469, 477 Radiometer effect, 315 Radium, 314, 463, 468, 470, 474 lessons of, 463 et seq. Raindrop, 435, 440 Range of light waves, 395 Rate of oscillation, 42 Ratio of units, 237 Rayleigh, Lord, 250, 392, 419, 435, 489/2. Reflected light, amount of, 261, 262 ripples, i Reflexion, 252, 261—266, 305, 330 by magnetic medium, 270 concentration of light by, 253 Reflexion, metallic, 253 model of, 261 — 267, 357 Refraction of electric waves, 261—288 index and spec. ind. cap., 243—247 Reluctance, 153 Residual charge, 37 Resilience, 319 Resistance, 68, 69, 490, 491 an impedance, 490, 491 effect of magnetic field on, 281 of commutated circuit, 488 to alternating currents, 489, 490 magnetic : see Reluctance Resonance, electric, 292, 400 Retentivity, 157, 159, 162 Return circuit, 28 Reuleaux, 96, 97 Reversible heat, 115, 116 Richardson, 339 Righi, 282, 442??. Rigidity, kinetic, 320 and fluidity of ether, 16, 17, 214, 215 mechanical, 320 of moving fluid, 17, 201, 256, 371, 382 Ring magnet, 154, 158, 205—208 Ripples, i Rise of induced current in secon- dary circuit, 190 — 194 Rontgen, 428, 433 Rotating discharge in vacuum-tube, 140 magnet producing current, 144 Rotation experiments, 135 — 145 of magnet by current, 143 of plane of polarization, 268, 355 of polarization by Leyden jar discharge, 406 — 408 of viscous liquid, 98, 99 Rowland, 279, 424, 494 Royal Institution, 290, 386;;. wall-paper, 401 Royal Society, 236 Ruhmkorff coil, 492 Rutherford, 447, 464, 468, 474 5i6 INDEX S. SABINE, 358 Saturation of iron, 155 Savary, 396 Schiller, 398 Schuster, 124, 125, 432, 442 Screen, magnetic, 193 Second law, Faraday's, 75 Secondary conductor, 208 Secondary circuit, 492 generators, 207, 492 rise of current in, 190 — 194 Seebeck, 116 Selective absorption, 246 Selenium, 283, 358 Self-contained states, 160 Self-induction, 88, 92, 93, 222, 483, 484, 488, 493 coefficient of, 484 effect of, on signals, 233 explained, 391, 392 model of, 182 — 189 Sense organs, 453, 455, 458, 461 Shadow photography, 428 Shearing of ether, 322, 331, 379 stress, 42 Signalling by wire, 197, 230 speed, 28, 197, 229, 236, 493 Signals affected by capacity, and self-induction, 232, 233 Silbermann, 431 Simple harmonic motion analyzed, 272 harmonic motion period, 221, 222 Slip and spin, 185, 188, 189 Smith, Willoughby, 358 Soaking in, 36, 38 Soaking out, 36, 38 Soap-bubble, 436 Society, Royal, 236 Soddy, 474 Solenoid, 336, 337 Solid angle, 486 perfect, 320 Solids, properties dependent on past history, 159 Sound, propagation of, 71, 371 vibrations, i§ Spark-length affected by light, 284 Spark, light of, one starting another, 284 Sparks, in wall paper, 401 musical, 402 — 406 Specific heat, 121 of electricity, 120 Specific inductive capacity, 36, 51, 214, 215, 321 compared with index of refrac- tion, 243 — 247 not constant, 273 probable real value, 226 Specific resistance, 68, 69 Spectroscopy, 446 Speed : see Velocity Spherical radiator, 299 Spin and slip, 185, 188, 189, 328 Spinning and quiescent wheels, ?83. Spiral liquid jet, 140 Spring analogue to Leyden jar, 388-390 Spurious charge, 53 Stable atomic aggregates, 323 Stationary waves, 265 Hertz's, 229 Steel, magnetization of, 160 rigidity of, 372 state of, 159 Stokes, Sir G. G., 9, 104, 283, 303, 305, 439, 440 Memorial volume, 237 Stoney, 418, 419, 421 Strain and stress in light-waves, 333. in dielectric, 20, 37 in medium, causing attraction and repulsion, 27 of medium, recovery, 220 Stratified condenser, 35 — 41 Stream-lines, 103 — 105 Stress in ether, 338 in magnetic medium, 167 — 170 Structure of the ether, 319 Strutt, 448, 467 Sub-permanent magnetism, 158 Sunlight, energy of, 333 Sunshine, force of, 314 tropical, power of, 30872. INDEX Surface, 53 conduction, 99 Surgings in circuit, 402 Syntony, 292, 293 T. TELEGRAPH, function of wire in, 96, 100, 196, 197, 230—235 Telegraphic return circuit, 28 Telegraphing methods of, 194 — 197 affected by capacity and self- induction, 232, 233, 494 speed of, 194, 493 Telephone currents, 100 Temperature raised by current, 70 Tenacity, electric, 218 Tension along magnetic lines of force, 1 66 — 171 Tesla, his dynamos, 307 Thermal E.M.F., 116, 119, 207 Thermo-electric connection, 281 currents, forces, 18072. pile, 117, 118 view of Hall effect, 280 Thompson, S. P., 122, 140, 281, 358 Thomson, Prof. E., 315 Thomson, Prof. J. J., 124, 25772., 339, 340, 384, 4*7, 432> 434, 439, 442, 467, preface Thorium, 469 Time necessary to start current, 98, 189, 191 of Faraday effect, 405 Tourmaline, 122 Traces, 363 Tram-car, electric, 95 rope, 95, 364 Transfer of energy to distance, 93— 95» 194—197 of heat, water, and electricity, 66 Transformers, 162, 492 Transmission of energy, 95 — 106, 330 of light, 371, 457 Transparency, grades of, 314 of insulators, 261 — 264, 356 of low-temperature radiation, 3X3 Transverse vibrations, transmissible by ether, 224, 231 • waves, 17, 321, 371, 457 Trouton, 288^., 302, 304, 305, 3i6 Tuning, 291 Tuning-fork analogue to discharge, 223—225, 395 Two-fluid theory : see Dual view of electricity U. ULTRA-VIOLET light, 312. 442 effect on sparks, 284 rays, 258 Undulatory, meaning of word, 352 Unit, natural, of electricity, 75 Units, artificial systems of, 227 electro- magnetic, 75 ratio of, 237 system of, 496 Universe, unseen, 319, 502 Uranium, 467, 474 V. " F," mode of determining, 236, 237, 353 Vacuum-tube, 307, 427, 431 rotating discharge in, 140 Vacuum versus Plenum, 359 Valency, 74 Varying current, 181 — 194 magnetic field and electrostatic charge, 143, 204, 207 Velocity of electric pulses along wires, 235, 236, 237, 353 of electric radiation, 226, 228 —247 of gravitation, 224 of ions, 84, 85 5i8 INDEX Velocities of light and electric waves compared in substances, 145 Velocity of light, 243—247, 335, 370, 373> 374 of magnetic drift, 336 of signalling, 28, 197, 229, 236, 493 of transverse vibration, 372 of wave propagation, 223 on wire same as in space, 494 Very and Langley, 311/2. Vibration, atomic, frequency of, 256—260, 378 direction of, 303 et seq. maintenance of, 317 range of, 459 Views concerning ether, 318 — 341 Viscosity analogue of starting current, 97 Viscous liquid, rotation of, 98, 99 Vital mental processes, 462 Volta-effect, cord-model of, 1 14 Kelvin form of, 113 Voltaic-battery, 106 — 109 E.M.F., 203 Voltameter, 73, 108 Voltametric law, 73 Volta's contact force, 108 — 114 Vortex, elasticity of, 384 atoms, 382-386 motion, 16 ring, electric, 167, 182, 205, 411 theory of matter, 384 — 386 vibration of, 384 Vortices, 15, 382 — 386 W. WALL paper, sparks in, 401 Waste radiation, 249, 250 Water-ram, 87 Wave, definition of, 351 Wave, ethereal, 2 length, electric, 239, 240 motion, 16, 225 propagation, 222 — 225, 321, 394 Wave-length and opacity, 312, 489 of radiation, 489 Waves, Hertz's, 229, 286 affecting the eye, 459 length and Leyden jar, 239, 488 luminous, 242 on wires, 232 et seq., 237, 493, 494 stationary, 265 transmission of, 330 transverse, 17, 321, 371, 457 Weber's theory of diamagnetism, 148—153 Wheatstone's kaleidophone, 427 Wheels, double series of, 255 Whirl, mechanical, 324 of electricity, 89, 131, 167 — 170, 348 Whirls, magnetic, 167 — 171 Wiedemann and Ebert, 284 Williams, 502 Wilson, 438, 440 Wimshurst machine, 298, 405 effect of, on sound, 273 Wire, function of, 92, 96, 230 pulses along, 494 Wireless telegraphy, 296, 298, 3 1 1 Work done in magnetic cycle, 161 X. X-RAD1ATION, 429 z. ZEEMAN, 423—427, 432, 433, 441, 443 K. CLAY AND SONS, LTD., BREAD ST. HILL, E.G., AND BUNGAY, SUFFOLK. RETURN TO the circulation desk of any University of California Library or to the NORTHERN REGIONAL LIBRARY FACILITY Bldg, 400, Richmond Field Station University of California Richmond, CA 94804-4698 ALL BOOKS MAY BE RECALLED AFTER 7 DAYS • 2-month loans may be renewed by calling (510)642-6753 • 1-year loans may be recharged by bringing books to NRLF • Renewals and recharges may be made 4 days prior to due date, DUE AS STAMPED BELOW 2 8 2000 12,000(11/95) OF CALIFORNIA LIBRARY .-— -...^ ^ QJS^\D OF CALIFORNIA LIBRARY OF THE UNIVERSITY OF CALIFORNIA OF CALIFORNIA LIBRARY OF THE UNIVERSITY OF CALIFORNIA. 