444 



INDEX. 



Siemens, Carl Wilhelm, his dynamo- 

 electric machine, 409 

 his longitudinal armature, 407 

 Sight affected by current, 228 

 Silurus, the, 68 

 Sine galvanometer, 201 

 Single touch, 92 

 Single-fluid cells, 169 

 Siphon-recorder, 431 

 Smee's Battery, 165, 169 

 Soap-bubble, electrified, 3 

 Solenoid, 327 



magnet, 314 

 Solid angles, 133 

 Solidification, 61 ^ 

 Sound 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 capacity, 21, 49, 268, 



272 



Speed of signalling, 274, 275, 296, 430 

 Sphere, distribution of charge over 



35 (a), 248, 249 



Spottiswoodti William, on striae, 294 

 Stewart, Balfour, on atmospheric 



electricity, 308 

 on magnetic storms, 144 

 Storms, magnetic, 145 

 Standards of resistance (see Resist- 

 ance Coils) 

 Strain, dielectric, 56 

 Strength of current, 158, 179 



,, in magnetic mea- 



sure, 195, 196 



Strength of magnet pole, 102 

 of magnetic shell, 315 

 Striae in vacuum tubes, 292, 294 

 Sturgeon, IV., invents the electro- 

 magnet, 326 



Submarine telegraphs, 429 

 Stilzer's experiment, 227 

 Symmer, on two kinds of electrifica- 

 tion, 4 



Surface-density of charge, 35, 248 

 limit of, 248 

 of magnetism, 127, 311 

 Swammerdain! s frog experiment, 229 

 Swans electric lamp, 374 



Tait, Peter Guthrie, electrification 

 by evaporation of sulphate of copper 

 solution, 63 



j Tait, Peter G^^thrie, thermo-electric 



! diagram, 383 



1 Tangent galvanometer, 199 



! Taste affected by current;- 227 



j 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 Reis's, 434 

 currents of, 229 

 Dolbear's, 436 

 Edison's (carbon), 436 

 Graham Bell's (articulating), 



Varley's (condenser), 272 

 Temperature affects resistance, 183 



affected by resistance, 369 

 Tension of electrostatic forces, 248 



(footnote) 



Terquem, A. y parrot-cage experi- 

 ment, 31 



Terrestrial Magnetism, 88, 135 

 Test for weak currents (chemical), 218, 



286 



for weak currents (physiologi- 

 cal), 229 



Testing for faults, 427 

 ! Tetanisation produced by interrupted 

 | currents, 230 

 j Theories of Electricity, 6, 300, and 



preface, ix. 

 j Theories of Magnetism, 91, 115 



,, Ampere's, 338 

 Maxwell's, 115 

 Theory of Electrolysis, Joule's, 414 



Grotthusfs and Clausius's, 418 

 Thermo-electric currents, ) 

 Thermo-electricity, ) 7 > 379 



Thermo-electric Diagram, 383 

 Thermo-electromotive Series, 382 

 I Thermo-pile, 384 



j Thompson, Silvanus Phillips, on 

 magnetic figures due to cur- 

 rents, 334 



on Magnetic writing, in 

 on Nobili's rings, 432 

 on Positive and Negative 



states, 300 

 on opacity of Tourmaline, 390 



(footnote) 

 Thomson, Joseph J., on Contact 



Electricity, 73 



Thomson, Sir William, the Re- 

 plenisher (or Mouse-Mill), 45, 261, 

 262 



