None
445 Coercive force. 89 Colour of spark, 289 Columbus, Cristo/ero, en magnetic variation, 136 Combustion a source of electrification, M Commutator, 375, 309, 407 Compass (magnetic), Mariner's, 79, 134 Compound circuit, 181 Condensation 48 Condensers., 48, 267 standard. 276 use of, 275 Condensing electrorcope, 71, 149 Conduction, 27, 158 by liquids, 205 of gases, 158 Conductivity, 158, 346, 348- Conductors and Non-ccnductors, 8, 27 Consequent Poles, 104, 109 Contact Electricity, 71, 149 Series of metals, 72 Continuous electrophorus, 23, 45 Convection of Electricity, 45, 337 Convection-currents, properties of, 337 Convection-induction machines, 45 Convection-streams at points, 35 (a), 43. 249 Cooling and heating of junction by current, 380 Cost of power denved from electricity, 3?8 Coulomb^ Torsion Balance, 13, 119 Law of Inverse Squares, 16, 117, 119, 235, 245 on distribution of charge, 35, 248 Coulomb, the, 32 3 Couple, magnetic, 123 Crookea, William, on shadows in electric discharge, 293 on repulsion from negative electrode, 300 Crown of cups., 1 51 Cruickshank' s Trough Battery, iCa Crystals, electricity of, 06 dielectric properties of 370 magnetism of, 343 Crystallisation, 61 Cumming 's phenomenon, 382 Cuneii!,' discovery of Leyden Jar, 52 Current, efier:!.' ilue to, 153 Current Electricity. 147 strength of, 158, 179 ,, unit 01, 196 Current -re\er?er (see Commutator) Current sneeU, 340 Curvature arfects surface-density, 35, 340 Curves, magnetic (see Magnetic Figures) Cuthberlson's Electric machine, 38, 289 Cylinder Electrical machine, 39 DAILY variations of magnet, 14* Dalibard's lightning-rod. 302 Daniell's Battery, 170 Davy's (Marie) Battery, 175 Davy, Sir Humphrey, magnetisation by current, 326 discovers electric light, 371 electrolyses caustic alkalU hes, 41 De Haldat. magnetic wntmg, .11 De la Rive s Floating Battery, 194 DelaRue, Chloride of Silver Battery, 174, 291 on electrotyping, 420 on length of spark, 291 Declination, Magnetic, 136 variations of, 136, 141 Decomposition of water, 206, 413 of alkalies, 417 Deflections, method of, 118, 123, 3253 Dellmann's electrometer, 260 Density (surface) of charge, 35, 248 magnetic, 127, 311 Deivar, James, on currents generated by light Li the eye, 231- his capillary electrometer, 225 Diagram, thermo-electric, 383 Diamagnetic polarity, 342 Diamagnetism, 87, 339 of flames, 344 of gases, 340 Diaphragm currents, 224 Dielectric capacity (see Specific IK ductive Capacity) strain, 56, 272 strength, 284 Dielectrics, 8, 49, 270 Differential Galvanometer, 203 Dimensions of Units (see Units) Dip, or Inclination, 137 variation of, .141 Diplex signalling, 428 Dipping Needle, 137 Discharge atfected by magnet,. Discharge affected by points, 43, 390, 302 effects of, 43, 984, 986 electrical, 7, 280 glow, zoo, 302 (footnote) Emit of, 248 sensitive state of, 294 velocity of, 296 Discharger, Discharging-tongs, 51 Universal, 54 Disruption produces electrification, 60 Dissectable Leyden Jar, 55 Dissipation of Charge, 299 Distillation, electric, 223 Distribution of Electricity, 28, 35, 348, 349 of Current, 240 of Magnetism, 104, 122 Divided Circuit, 353 Touch, 93 Dolbear*s Telephone, 436 Doubler, 23, 45 Double Touch, 94 I>ry-Pile, 182, 264 Huboscq s Lamp, 372 "Du Fay's experiments, 4, 37 Duplex Telegraphy, 375, 428 duration of Spark, 296 Huter on Electric Expansion, 273 Dynamic Electricity (see Current JLlectricity) Dynamo-electric machines, 408 Dyne, the (unit of force), 355 EARTH, the, a magnet, 88 currents, 275, 403 electrostatic capacity of, intensity of magnetisation, 313 magnetic moment of,°32sb used as return wire, 423 Earth's magnetism (f Magnetism) Edison, Tkomas A lvat electric lamp, 374 ; steam -dynamo, 411 (5X carbon telephone, 436 meter for currents, 216 quadruple* telegraphy, 438 Edlur.d on galvanic expansion, cri Eel, electric (Gymnotus), 68 ' Electrics; i Electric Air-Thermometer, 288 Cage, 34 Candle, 573 Clocks, 433 Distillation, 293 (Fiietiona!) machines, 39 Electric Egg, the, 393 Expansion, 273 Force, 153 (Jooincte\ 341 Fuze, 286, 370 Images, 250 Kite, 302 Lamps, 373 Light. 37* Mill or Fly, 43 Oscillations, 295 Osmose, 232 Pistol, 286 Shadows, 293 Shock, 226 Wind, 43 Electricity, theories of, 6, 300 Electro-capillary phenomena, 225 Electro-chemical equivalents, 211, 211 Electro-chemistry, 4x2 Electrodes, 207 unpolarisable, 331 Electrodynamics, 331 Electrodyaamometer, 336,378 (bis.) Electrolysis, 208 laws of. 211, 4x4, 417 of copper sulphate, 209 of water, 207, 413 theory of, 4x4 Electrolytes, 207, 417 Electrolytic ccnvection, 41} Elcctrcniagaets, 98, 326 laws of, 330 Electromagnetic engines (motors), £75 Electromagnetics, 3x0 Electromagnetic theory of Light, 390 Electromagnetism, 326 Electrometallurgy, 419 Electrometer, absolute, 261 attractcd-disc, 261 capillary, 225, 265 Delltnann's, 260 divided-ring, 71 Peltier's, 260, 307 portable, 261 quadrant (Sir W* T 362 repulsion, 260 torsion, 15 trap-door, 261 Elcctromctive-force, 155 measurement of, 360 unit of, 322, 323 Electromotors, 375 Electro-Optics, 383 Electrophorus, 22 continuous, 23, 45 Electroplating, 421 Electroscopes, n Bohnenbtrgsr1 1, 13, 064 INDEX. 447 Electroscopes, Benntfs gold-leaf, 13, Fechneifs, ^64 Gaugain's discharging, 259 Gilberts straw-needle, 12 Hankel's, 264 Henley's quadrant, 14 Pith-ball, 2, 3 Volttfs condensing, 71, 149 Electrostatics, 7, 233 Electrotyping, 420 Energy of charge of Leyden Jar, 270 of electric current, 378 Equator/ Magnetic, 78 Equipotential surfaces, 242, 310 (f) magnetic, 310 Equivalents, electro-chemical, 212 Erg, the (unit of work), 255 Evaporation produces electrification, *-63l 3°3 u discharge by, 323 Everett, James £>., on atmospheric electricity, 307 on exact reading of galvan- ometer, 202 (footnote) on intensity of magnetisation ^ of earth, 313 Expansion, electric, 273, 386 Extra-current (self-induced), 404 FAILURE and exhaustion of batteries, 1 60 Fall of Potential along a wire, 263, 357 Farad, the (unit of capacity), 276, 323 Faraday, Michael, molecular theory of electricity, 6 chemical theory of cell, i56 dark discharge, 290 Diamagnetism, 339, 340, 344 discovered inductive capacity, 21, 269, 271 Discovery of magneto • induc- . tion, 391 Electro-magnetic rotation, 375 experiment on dielectric polar- isation, 272 gauze-bag experiment, 31 nollow-cube experiment, 31 ire-pail experiment, 34 laws cf electrolysis, 211, 214 Magnetic lines-of-force, 108, 402 on A rago's rotations, 401 on dissipation of charge, 291 on identity of different kinds of electricity, 217, 218, 286 Voltameter, 214 Faraday. Michael, Magneto -optic discovery, 387 predicted retardation in cables, 274 Faure's Secondary Battery, 415 Favre's experiments on Heat of Cur- rents, 368 Feckner's electroscope, 264 Feddersen, W., on electric oscilla- tions, 296 Ferromagnetic substances, 339 Field, magnetic, 105, 191, 312 Figures, magnetic (see Magnetic figures) electric, 297 Fire of St. Elmo, 302 {footnote) Flame, currents of, 291 diamagnctism of, 344 discharge by, 7, 291 produces electrification, 62 Fleming's Battery, 182 Fontana on electric expansion, 273 Force, electric, 155 (footnote), 241, 251, 252 magnetic, 83, 155 (footnote), 328 electromotive, 155 Foucault's Regulator Lamp, 372 Interrupter, 398 „ Franklin, Benjamin, discovered action of points, mentioned in, 35 (c), 43. 3™ cascade arrangement of Leyden Jars, 279 _ Electric Chimes, 43 Electric Kite, 302 Electric portraits, 288 his charged pane of glass, 47 invents Lightning Conductors, 3°S kills turkey by electric shock, 256 One-fluid theory of Electricity, • ,0 on seat of charge, 55 theory of the Aurora, 309 " Free " electricity, 24, 149 (footnote) Friction produces electrification, i, 10 Frog's legs, contractions of, 148, * Froment s Electromotor, 375 Fuze, electric, 286, 370 Gaivani, Aloysius, observed move- ments of frog's leg, 148 44* INDEX. Galvant, Aloystus, on preparation of frog's limbs, 229 on Animal Electricity, 231 Galvanic Batteries (see Voltaic Batteries) Electricity (see Current Elec- tricity) Taste. 237 Galvanism (see Current Electricity) Galvanometer, 107 absolute, «oo astatic, 198, 331 ballistic, 204 constant of, 200 differential, 203 f>n Bin Reytnond't, 331 tfelmJtoltt's, IQO reflecting (Sir W. Thomson's). or mirror, aoa sine, 201 tangent, 199 Galvanoplastic (see Electrolysing) Gal \anoscope, 188 Gas Battery, 416 Gases, resistance of, 158 Gassiot, /. P , on stric=, 294, 300 Contain, Jean Mothte, discharging electroscope, 259 on Pyroelectricity, 66 Tangent Galvanometer, 199 G.fitss, F., invented absolute measure- ment, 32sa magnetic moment of earth, magnetic observations, 313 Gay, Lussac, on atmosphenc elec- tricity, 307 Geissler's tubes, 291 Geniez on electric distillation, 223 Gil-son and Barclay on dielectric capacity of paraffin, 270 Gilbert, Dr. William, discovers electrics, i discovered magnetic reaction, 83 discovers that the earth is a magnet, 88, 135 heat destroys magnetism, 09 his balanced - needle electro- scope, 12 observation of moisture, 9 observations on magnets, 78 on de - electrifying power of flame, 291 on magnetic figures, 108 on magnetic substances, 85 on magnetic permeability, 84 on methods of magnetisation, «6, 97 Gilding by Electricity, 431 Globular lightning, 304 Glow Discharge, 290, 302 (footnote] Glowing of wires. 369 Gold-leaf Electroscope (see Electro- scope) Gordon, J. £. H., on magneto-optic rotatory power, 387 on dielectric capacitj, 270, 271 on length of spark, 291 Gramme's dynamo-electric machine, 410 Gravitation Battery, 176 Gray, Stephen, discovers conduction, on lightning, 302 Grotthuss' theory, 160, 418 Grove, Sir William R., his ,Gai Battery, 416 Grove's Battery^ 171 magnetic experiment, 113 on electric property of Flame, 291 Guard-ring, Guard-plate, 248, 261 Guericke, Otto von, discovered elee trie repulsion, 3 invents electric machine, 38 observes electric sparks, 9 Gunpowder fired by electricity, 286, 288, 370 Gymnotus (electric eel), 68, 318 Halts phenomenon, 337 Hankers electroscope, 264 Harris, Sir tr'. Snow, his unit Leydenjar, 259 attracted • disc electrometer, 261 on length of spark, 291 Heat, effect of, on magnets, 99, too ,, batteries, 183 „ conductivity, 349 Heating effects of currents, 171, 366, 380 due to magnetisation, 113, 401 effect of sparks, a88 ,, dielectric stress, 3-73 local, at electrodes, 41' Helmholtz, Hermann L. on effect of current on s% . 2?1 Electrolytic convection, 418 Equations of Self • induction, -,f>5 Galvanometer, 199 Henry, Joseph, invented tii* "sounder," 423 INDEX. 449 Henry, Joseph^ on induced currents of higher orders, 406 Holt*t W,, his electric machine. 46 on electric shadows, 393 (, foot- note] on tubes having unilateral re- sistance, 300 Hofkinson, John, on dielectric cap- acity of glass, 970 on residual charge and its return, 53, 872 Horizontal component of magnetism, 123, 138 Hughes, David Edward, the Print-. ing Telegraph, 423 the Microphone, 437 Humboldt, Alexander von, on elec- tric eels, 68 discovers galvanic smell, 228 produced electric contractions in fishes, 229 Hunter, Dr. John, on effect of current on sight, 228 Hydroelectric machine, 44 IMAGES, electric, 950 Incandescent electric lights, 374 Inclination (or Dip), 137 variation of, 141 Index Notation, 3250 Induced charges of electricity, 18 currents, 391 Induction (electrostatic) of charges, if (ma.S~netic\ Hnes of, 89 (magnetic) of magnetism, 89, 3*3 „ coefficient of, 342 (magneto-electric) of currents, 39» Induction-coil or Inductorium, 398 Induction-convection machines, 45 Ind ictive-capacity, specific, 21, 49, »oS. 272 Insulators, 8, 27 intensity of current, 179 of earth's magnetic force, 138, 3s 5a Oi magnetic field, 312 of magnetisation, 313 Inverse Squares, Law of, 16, 117, 235, *45 Inversion, Thermo-electric, 382 Ions, 210 Isoclinic lines, 139 Isogomc lines, 139 JacoU, Merits Hermann, on local action, 162 discovers galvanoplastic pro- cess, 4:0 his boat propelled by electricity, theory of electromotors, 377 Jablochko_ff, Paul, his battery, 182 electric candle, 373 Jar, Ley den, 51 v capacity of, 50, 267, 277 „ cascade arrangement of, 279 ,, discharge of, 51, 295 „ discovery of, 53 ,, energy of charge of, 278 „ seat of charge of, 55 „ spark of, 289, 296 „ theory of, 267 Unit, 259 Jenkin, Fleemingt on cable as con- denser, 274 on retardation in cables, 296 Joule, James Prescott, on effects of magnetisation. 113 Law of Heat of Current, 367 Mechanical equivalent of Heat, 255. 414 ou atmospheric electricity, 306 on lifting • power of electro- magnet, 326 /ow//-effect, the, 380, 367 KATHODE, 207 Kation, 210 Keeper, 101 Kerr, Dr. John, Electro • optic dis- coveries, 273, 386 Magneto-optic discoveries, IIA, 388 Kinntrsley, Elijah, Electric Ther- mometer, 288 Kinhho/. Gustav, Laws of Branched Circuits, 353 Kite, the electric, 302 Kohlrausch, F., on residual charge, 272 on electro-chemical equivalent, an (footnote) LAMELLAR magnetisation, 107 INDEX. Laminated magnets, 95 Law of Inverse squares, 16, 117, 335, »45 Leakage, rate of, 299 LectencM't Batteryt 173 Le Bailiff on diamagnetism of antimony, 339 Lemonnicr discovers atmospheric electricity, 306 Length of spark, 391 Lettifs Law, 396 alcohol calorimeter, 367 Leyden Tar (see Jar) Licktenoerjf t figures, 297 Lifting-power of magnets, 103 of electromagnets, 328 Light affects resistance, 389 • Electric, 371 Electromagnetic theory of, 365, polarised, rotated by magnet, . "4. 387, 388 Lightning, 9, 302, 304 conductors, 32, 305 duration of, 296, 304 Lines-of-force, electric, 243 due to currents, 191, 329, 334 magnetic, 89, 108, 310, 312 Lifpmann, G., Capillary Electro- meter, 225, 265 Liquids as conductors, 205 'resistance of, 348 " Local Action " in batteries, 161 Lodestone, 76, 340 " Long-coil instruments, 353 Loss of Charge, 15, 299 Louis XV. electrifies 700 monks, 226 Lullin's experiment, 285 Luminous effects of spark, 289, 400 M MACHINE, Alternate-current, 411 Electric, 38 Compound-wound, 411 convection-induction, 45 cylinder, 39 dynamo-electric, 408 Holttts, 46 hydro-electrical, 44 invention of, 38 magneto-electric, 407 plate, 44 Winter's, 40 Magne-crystallic action, 343 Magnet, breaking a, 106 Magnets, natural and artificial, 76, 77, 326 Magnetic actions of current, 184, 318, 396, 339, 334 Magnetic attraction and repulsion, Co, xxo cage, 84 curves, 108, 191 field, 105, 191, 312, 327 figures, xo8, 109, no, 191 ,, theory of, 126 fluids, alleged, qx force, 83, 310 (e) ., measurement of, 118 • 3a mdt iuction, 89 „ coefficient of, 342 iron ore, 76 lines-of- force, 89, 108, 109, xxo, 316 lines-of-force of current, 191, 320, 329 maps, 139 meridian, 136 metals, 86, 339 moment, 123 (/ootnot«\ 313, Sff needle, 79, 134 oxide of iron, 76, 172 (_footx:*s} paradox, a, 128 pole, unit, 125 potential, 310, 314, •* 13 proof-plane, 402 saturation, 102, 330 „ Beetz, on, 115 screen, 84 shell, 107, XQ2, 311 (K) „ > force due to, 137 „ ' potential due ip, 127, 3-- storms, 145, 309 substances, 85, 339 units, 321 writing, xxx Magnetisation, coefficient of (or sus- ceptibility), 89, 313 intensity of, 313 lamellar, 107 mechanical effects of, 1x3 methods of, 92-98, 327 solenoidal, 107 sound of, 113, 434 time needed for, 330 Magnetism, 76 action of, on light, 114, 387 caused by heat, 98 destruction of, 99 distribution of. 104 of gases, 339, 387 lamellar, 107 laws of, Si, 116, 310, 330 permanent, 90, 3x3 residual, 102 INDEX. 451 Magnetism, solenoidal, 107, 314 temporary, 90, 102, 313 terrestrial. 88, 135 theories of, 91, 115, 338 unit of, 125 Magnetite, 76 Magneto-electricity, 74, 391 Magneto-electric induction, 391 machines, 407 Magnetographs, 146 Magnetometer. 124 self-registering, 146 Magneto-optic Rotations, 387 Magnets, artificial, 77 compound, 95 forms of, 101 lamellar, iy/ laminated, 95 methods of making, 92 98 natural, 76, 101 power of, 103 Mance's method, 361 Maps, magnetic, 139 Mariner's Compass, 134 Marked pole, 80 Mascart, J£.t on self • registering apparatus, 288 on atmospheric electricity, 308 Mattewci. Catlo, on physiological effects, 68, 230 on electromotive - force1 in muscle, 231 Maynooth Battery (see Callans Battery) Maxu U, fames Clerk, Electro- magnetic theory of Light, 337. 365. 390 on Electric Images, 250 on protection from Lightning, 32, 3<>5 on residual charge of jar. 272 on self-repulsion of circuit, 334 rule for action of current on magnet, 193, 317 Theorem of equivalent Mag- netic shell, 192, 318 Theory of Magnetism, 115 Measurements, electrical, 355-363 magnetic, 118, 3253. Mechanical effects of Discharge, 284, 43 etects of magnetisation, 113 ,, in dielectric, 272 Medical Applications of Electricity, 232, 369 Megohm, 323 Meidinger's Battery, 176. Meridian. Magnetic. 136 Metallo-chromv, 432 Microfarad condenser, 276 Microphone, the, 437 Milli-ampere, 323 M imosa. the, electric behaviour of, 230 Minolta's Battery, 176 Mirror Galvanometer, 203 Moisture,* effect of, i, 8, 2cp Molecular theory of Electric action, 6 actions of current, 221 Moment of Couple, 123 of inertia, 32 $a magnetic, 123 (Jbotnoie), 3253 Morse Telegraph instrument, 425 Mouse-mill (sea Repfenisher) Mailer, Johannes, on strength of electromagnets, 330 Multiplier, Sthweigger' s, 18g Muscular contractions, 229, 231 Musschenbroek, Peter van, dis- covery of Ley den Jar, 52 on Magnetic Figures, no Mutual Induction, coefficient of, 320, 397 Mutual Potential, coefficient of, 320 N Napoleon IIJ.'s Battery, 182 Needle, magnetic, 79 Needle Telegraph, 424 Negative electrification, 4, 300 Newton, Sir Isaac, observations on action and reaction, 83 bis lodeslone, 103 suggests electric origin of light- ning, 9, 302 suggests glass for electric machines, 38 Niaudefs Battery, 173 Nobili, Leopoldo, on muscular con- tractions, 68 on currents of animal electricity, 231 discovers N chili's rings, 422 Non-conductors, 8 Non-electrics, 2 North and south, 81, 135 North magnetic pole, the, 81, 135 Null methods, 263 Oerstedt, Hans Christian, discovers magnetic action of current, 184, 185, 191 Ohm, Dr. G. S., 179 " Ohm's Law," 160, 345 452 INDEX. Ohm, the, or unit of resistance, 333 ,, determination 'of, 364 One-fluid theory of electricity, 6 Optical strain, electrostatic, 386 ,, electromagnetic, 387 Oscillations, electric, 295 method of -(for electrostatics), 120 (footnote), 235 method of (for magnetic mea- surement), 120, 121, 122, 32$a Osmose, electric, 222 Other sources of electricity than fric- tion, 10, 57 Ozone, ao8, 298, 302 (footnote) Page, Charles G.t discovers magnetic sounds, 113 Parallel currents, laws of, 333 Paramagnetic, 339 " Passive" state of iron, 172 (footnote} Peltier, Athanase, his electrometer, «6p, 307 heating effect at junctions, 380 theory of thunderstorms, 303 Penetrative, power of discharge, 284 , Periodicity of aurora and magnetic storms, 144, 145, 309 Perry aad Ayrton (see Ayrton and Pitt, Voltaic, 150. Pith-ball electroscope, 2, 3 Phosphorescence caused by discharge, 292 Photo -voltaic property of selenium, S»9 Photophbne, 389 Physiological actions, 226, 287 Plane, the proof-, 29 / ,, for magnetism, 402 Plant/, Gaston, his secondary bat- teries, 4^ . ^ on globular lightning, 304 Plants, electricity of, 69, 230 Plate condenser, 48, 268, 277 electrical machine, 40 Plucker, Julius, on masne-crystallic action, 343" Po^gendorff,J. C., his battery, 165 Points, density of charge on, 35, 249 discharge at, 39, 42, 43, 249 Polarity, diamagnetic, 343 magnetic, 82, 106, 1x5 Polarisation (electrolytic) in battery cells, 163, 414 of Voltameter, 973, 413, 415 remedies for, 165 , Polarised ligh* rotated by magnetic forces, 387 relay, 428 Poles of magnets, 7_8, 122 of pyroelectric crystals, 66 of Voltaic battery, 154 Porrefs phenomenon, 222 Portable electrometer, 261 Portative force, 103 Positive and negative electrification 4' 30? Potential, electric, 37, 237 „ zero, 37/-2S9 magnetic, 310, 314, 315 „ due to current, 318 mutual, of two circuits, 319, 320 Pouillet, Claude S. M., sine galvan- ometer, 201 tangent galvanometer, 199 Power, transmission of, 376 Practical Units, 323 Preece, William Henry, on space protected from lightning, 305 Pressure produces electrification, 65 Priestley, Joseph, on electric expan- sion, 273 Prime condtlctor, 39 Printing telegraphs, 423 Proof-plane, 20 „ o (magnetic), 402 Poisson on magnetism in crystals 343 Protoplasm, electric property of, 331 Pyroelectricity, 66 Quadrant electrometer (Sir W. Thomson's), 262 electroscope (Henley's), 14 Quadruplex telegraphy, 428 "Quantity" arrangement of cells, 1 etc., 181 • of electricity, unit of, \j, 236 Quetelet, E., on atmospheric elec- tricity, 308 Quincke, Georg, on diaphragm cur- . rents, 224 , on electric expansion. 273 on electro - optic phenomena, 386 Ray, electric (torpedo), 68 Recovery, elastic, 27* INDEX. 453 Redistribution of charge, 36 Reflecting galvanometer, 202 Registering magnetographs and elec- trometers, 146, 307 Reis, Philip, invention of telephone, 434 Relation between currents and mag- nets, 184, 318, 326, 391 between current and energy, between current and heat and light, 366 Relays, 426 Replenisher, 45, 261, 262 Repulsion and attraction of electrified 'bodies, i, 3, 18, 20, 66, 236 and attraction, experiments on, and attraction of currents, 331 and attraction of magnets, 76, 80 Repulsion electrometers, 260 Residual charge of Leyden jar, 53, 272 „ of cable, 274, 430 „ of Voltameter, 272, magnetism, 102 Resinous electricity, 4 Resistance, 27, 158, 179, 346 absolute unit of, 363, 364 affected by temperature, 349 „ light, 389 ,, sound, 436 as a velocity, 363 bridge or balance, 358 coils, 359 internal, of cell, 181, 350 ,, „ measurement of, 361 law's of, 347' measurement of, 356 of gases, 158, 348 of liquids, 158, 349 specific, 348 Retardation of currents through cables, 274, 296, 430 Retentivity (magnetic), 90, 313 Return shock or stroke, 26, 304 Reyntond, Du Bois, his galvanometer, 231 on animal electricity, 231 unpolarisable electrodes, 231 Rheocord, 356 Rheostat, 356 Rheometer, \ Rheoscope, > see footnote to 197 Rheotrope, ) Riess, Peter, on electric distribution, 35 Riess, Peter, on length of spark, 291 electric thermometer, 288 (foot- note). Ritchie's electromotor, 375 Rittcr, Johann IVilhelm, on action of current on sight, 228 his secondary pile, 415 on subjective galvanic sounds, 230 on the sensitive plant (Mimosa), 230 Rolling friction, 10 Romagnosi, Dr., discovers magnetic action of current, 18^ Romas, De, his electric kite, 302 Ronalds, Sir Francis, invented a telegraph, 423 Rotations, electromagnetic, 335 AragJs, 401 Rowland, Henry A ., on magnetic effect of electric convection, 337 on intensity of magnetisation, 3*3 Ruhmkorff's induction coil, 398 commutator, 399 electromagnet, 339 S St. Elmo's fire, 502 (footnote) Salts, electrolysis of, 417 Sanderson, J Bnrdon, on electric sensitiveness of carnivorous plants, 231 Sawdust battery, 158, 176 Sckiveigger 's multiplier, 189 Secondary batteries, 178, 415 Secular variations of magnetic ele- ments, 141 SeebecKs discovery of thermo-elec- tricity, 379 Selenium, photo-voltaic properties of, 389 Self-induction of circuit, 404 Self-recording apparatus, 146, 288, 307 Self-repulsion of current, 334 Sensitive plant, behaviour of, 230 Series, union of cells in, 171 Shadows, electric, 293 Sheet conductor, flow of electricity in, 354 Shell, magnetic (see Magnetic Shell) Shock, electric, 226 of current, 226 "Short-coil" instruments, 352 Shunt, 202, 353 Siemens, Carl Wilhelmt -on heating effect in Leyden jar, 373 454 INDEX. Siemens, Carl Wilkslxi, his dynaiuo- electric machine, 409 hit longitudinal armature, 407 Sight affected by current, 228 Silurui, the, 68 Sine galvanometer, 201 Single touch, 93 Single-fluid cells, 169 Siphon-recorder, 431 Sinee's Battery, 165, 169 Soap-bubble, electrified, 3 Solenoid, 329 magnet, 314 Solid angles, 133 Solidification, 61 S^und of magnetisation, 113 Sounder, the, 425 Sources of electricity, 10, 57 Spark, 9, 43, 281 duration of, 296 length of, 44, 291, 302 Specific resistance, 348 inductive cajscity, 21, 49, 268, 272 Speed of signalling, 274, 273, 296, 430 Sphere, distribution of charge ever 35(«), 248, 249 Spotiizivoode, William, on stnae, 254 Siffitia.rtt Balfojur, on atmospheric electricity, 308 on magnetic storms, 144 Storms, magnetic, 14; Standards of resistance (see Resist- ance Coils) Strain, dielectric, 56 Strength of current, 158, 179 „ in magnetic mea- sure, 195, 156 Strergth of magnet pole, 102 of magnetic shell, 315 Striae in vacuum tubes, 292, 294 Sturgeon) W., invents the electro- magnet, 326 Submarine telegraphs, 429 Sulser's experiment, 227 Symmer, on two kinds of electrifica- tion, 4 Surface-density of charge, 35, 248 limit of, 248 of magnetism, 127, 311 Swamme retain' s frog experiment, 229 Swatt'i electric lamp, 374 T Tait, Peter Gut Arse, electrification by evaporation of sulphate of copper solution, 63 Tait% Peter Gvikrie, thermo-electric diagram, 383 Tar ^ent galvanometer, 109 Taste affected by current, 227 Telegraph, electric, 423 Bain's chemical, 218 Morse's instrument, 425 needle instrument, 424 Telegraphy, diplex, 428 duplex, 428 quadruplex, 428 submarine, 429 Telephone, Philip Kei/t, 434 currents ot 229 Dolbear's, 436 Ediscn's (carbon), 438 Gralutm Bell's (articulating^ 435 Varleyfs (condenser), 272 Temperature affects resistance, 183 affected by resistance, 369 Tension of electrostatic forces, 248 (footnote) Terqitem, A., parrot-cage experi- ment, 31 Terrestrial Magnetism, 88, 135 Test for weak currents (chemica1), 218, 286. for weak currents (physiologi- cal), 229 Testing for faults, 427 Tetanisation produced by interrupted currents, 230 Theories of Electricity, 6, 300, aad preface, be. Theories of Magnetism, 91, 115 „ At/lire's, 338 „ Max-well's, 115 Theory of Electrolysis, Joule's, 414 GroltMtss's and Clavstus's, 418 Thermo-electric currents, ) Thermo-electricity, f ?°' 379 Thermo-electric Diagram, 383 Thermo-electromotive Series, 382 Thermo-pile, 384 Thompson, Sih'anus Phillipt, on magnetic figures due to cur rents, 33^ on Magnetic writing, nz on Nobilt's rings, 422 on Positive 'and Negative ^states, 300 on opacity of Tourmaline, 390 ( footnote) ' Thomson, Joseph. /., on Contact Electricity, 73 ; value of " v," 305 Thomson, Sir William, the Re- plenisher (or Mouse- Mill), 45, a6t. S02 INDEX. 455 Thomson, Sir William, Proof of Contact Electricity, 71 Attracted • disc Electrometers, 261 Divided-ring Electrometer. 71 Electric convection of Heat (the " Thomson-effect "), 383 Mirror Galvanometer, 202, 431 Modified Daniel Ts Battery, 176 on atmospheric electricity, 306 on Electric Images, 250 on length of spark, 291 on nomenclature of Magnet Poles, 81 (footnote) on sounds in condensers, 272 predicts electric oscillations 295 (footnote) Quadrant Electrometer, 262 Siphon Recorder, 431 Thermo-electric Diagram, 383 Water-dropping Collector, 307 Thunder, 9, 304 Thunderstorms, 302 Theory of, 303 Tinfoil Condensers, 47, 275 Tongs, Discharging-, 51 Torpedo (electric fish), 68, 218 Torp^doe^, fuzes for firing, zao, 370 Torsion affected by magnetisation, 1 1 _, Torsion Balance, or ) (Coulomb's) Torsion Electrometer ) 15, 119 Total action of magnet, 3253 Tourmaline, 66, 297, 390 (footnote) Transformers, 400 [376 Transmission of P^wer by Electricity Tubes of force, 243, 311 Two-fluid cells, 170 Two-fluid theory, 6 Two kinds of Electrification, 4, 5 ,, Magnetic poles, Si TynJall, John, on diamagnetic polar- ity. 34* on magne-crystallic action, 343 UNIT Jar, 259 Unit (Electrostatic) of Electricity, 17, 236 (Electrostatic) of Capacity, 247 Magnetic Pole, 125 of difference of potential, 242 322, 323 of Electromotive-force, 322^ 323 of Resistance, 322, 323 of Strength of Current, 196, 3". 3*3 Units, Fundamental and Derived. 254. 255 dimensions of, 258, 324 Electrical (Electrostatic), 857 Electromagnetic. 322, 333 Magnetic, 321 Physical Dimensions of, 258, „ 324>. 35,1 Practical, 323 Universal Discharger, 54 Urtt Dr., on Animal Electricity, 229 " »," values of, 365, 390 Vacuum, induction takes place through, 50, 84, 89 partial, spark in, 9, 292 spark will not pass through, 291 Vacuum-tubes, 292 " Variation," the (see Declination) Variation of Declination and Dip, secular, 141 ; annual, 143 ; diurnal, 14? ; geographical, 136 Varley, C. A., his Telephone, 273 Vegetables. Electricity of, oo carnivorous, sensitiveness of, 230 Velocity of Discharge, 206 of Electricity (alleged), 296 of Light, 365, 300 Verdetjs Constant, 387 Vibration produces Electrification, 59 Vitreous electricity, 4 Volt, the, 323 Volta,Alessandro, his Electrophorus, 33 Condensing Electroscope, 71, 149 Contact Series, 72 Crown of Cups, 151 on Atmospheric Electricity, 307 on Contact Electricity, 71, 148 on Electric Expansion, 273 on Electrification due to com- bustion, 62 Subjective Sounds due to Current. 228 Volta's Law, 72, 148, 156 Voltaic Pile, 150 Voltaic Electricity (see Current Elec- tricity) Arc, 371 Battery, 154, 167; Pile, 130 Cell, simple, 152 Voltameter, 214, 215, 316 Voltmeter, 360 (ef) 456 INDEX. WATER, Electrolysis of, 206, 413 Weber, the 323 Wtber, IVilhelni,. the Electro-dyna- mometer, 356 on diamagnetic polarity, 342 Wheatstone, Sir Charles, on the brush discharge, 290 Automatic Telegraph, 423 Dynamo -electric Machines, 408 on supposed velocity of elec- tricity, 296 WheatstonJs Bridge or Bal- ance, 358 WiedciHann, Gusfav, on effect of magnetism on torsion, 113 Wiedemann, Gnstav, on diaraag- netism of platinum, 339 Wilde, Henry, Electric Candle, 373 Magneto-electric Machine, <oj Wind, Electric, 43 WShJer's Cell, 182 Wollastoiis Battery, 169 WiiUner on dielectric capacity, 270 Z Zant&onCt Dry Pile, 13, 182, 264 Zanotti, experiment on grasshoppe 229 Zero Potential, 37, 139 THE END, A 000 037 201 1. 