INDEX. 



425 



ductor, 355 ; copper, 356 ; fluids, 276 ; 



fused metals, 270; gutta-percha, 



282 ; India-rubber, 384 ; materials, 



264 ; pure metals, 266 ; and heat, 



266. 



Conduction of earth, 35. 

 Conductor, straight, 337 ; circular, 337. 

 Conicity of glass tubes, 329. 

 Constant of sensibility, 301. 

 Constadt's telegraph, 25. 

 Contact theory, 16. 

 Copper resistance, 296, 298. 

 Copying telegraph, 179. 

 Corrections for tubes, 331 ; for ends, 



332. 

 Code, Gauss and Weber's, 31 ; Morse's, 



87; Stohrer's, 175; Wheatstone's, 



49, 50. 



Coxe's telegraph, 20. 

 Currents, atmospheric, 202. 



Daniell's battery, 221, 327. 



Davy's telegraph, 42. 



Decomposition of water, 18. 



Depth of ocean, 292. 



De Sauty's key, 115. 



De Sauty's charge method, 379. 



Descent of bodies in water, 394. . 1% 



Diagrams of bottom, 352. 



Dial telegraph, Brequet's, 65 ; Kra- 

 mer's, 70 ; Siemens', 75 ; Wheat- 

 stone's, 45. 



Differential galvanometer, 353. 



Differential method, 358. 



Difficulties of solid normals, 339. 



Direct working instrument, 120 ; Dig- 

 ney's, 122; Siemens', 125; com- 

 plete, 127. 



Discovery of Leyden jar, 3 ; electro- 

 magnet, 24 ; earth conduction, 35. 



Discharge, 301. 



Distribution of battery, 289. 



Don Silva's telegraph, 10. 



Double-needle telegraph, 50. 



Double telegraphing, 154. 



Dover- Calais cable, 341. 



Dover-Ostend cable, 341. 



Dubois' galvanometer, 242. 



Durability of posts, 186; of cables, 388. 



Dynamometre, 398. 



Early observations, 1. 

 Earth conduction, 35, 

 Earth element, 230. 

 Earth plate, 200. 

 Eisenlohr's resistance, 255. 

 Elastic line, 390. 

 Electrics and non-electrics, 2. 



Electric permanency, 273; circuits, 

 206; action of pile, 17; measure- 

 ments, 285. 



Electrical magnitudes, 333. 



Electricity, static, 1 ; voltaic, 215 ; ne- 

 gative and positive, 3 ; distribution 

 of, 410. 



Electricity and lightning, 202. 



Electrification, 267. 



Electro -magnet, 24 ; laws of, 24. 



Electroscope, 8. 



Electromotive force, 333 ; measure of, 

 315 ; Fechner's method, 317 ; Ohm's 

 method, 320 ; Poggendorff's method, 

 320 ; Wheatstone's method, 319. 



Electromotive force of element com- 

 pared, 325. 



Elements, alum, 228 ; Bunsen's, 316 ; 

 Daniell's, 221 ; earth, 230 ; electro- 

 motive forces, 315 ; Grove's, 327, 

 328; Kramer's, 224; Meidinger's, 

 224 ; Siemens', 226 ; sulphate mer- 

 cury, 229 ; Varley's, 227. 



Embossing telegraph, 86. 



Erection of overland lines, 198. 



Escape of current, 391. 



Experiments of Guillemin, 125. 



Fabroni, 17. 



Failure of old Atlantic, 378. 



Faraday, induction, 25 ; magneto - 

 electricity, conduction, 25. 



Fardley's lightning- guard, 210. 



Faults, Hipps' method, 408. 



Faults, in insulation, 405 ; locality of, 

 307, 405 ; in conductor, 379, 381. 



Fechner's method, 319. 



Final tests of cable, 383. 



Fluids, conductivity of, 276. 



Forms of line insulators, 189. 



Formulae, astatic needle, 245 ; bisected 

 wire, 312; circular current, 236; 

 conducting powers, 264, 267 ; 

 pure metals, 267 ; alloys, 269 ; mer- 

 cury, 273 ; constant of sensibility, 

 307 ; correction for ends, 333 ; cor- 

 rection forconicity, 331 ; copper re- 

 sistance, 355 ; distribution, 263, 289 ; 

 differential method, 359 ; differential 

 galvanometer, 353 ; dynamometer, 

 398 ; effects of pressure, 365 ; elec- 

 tromotive force, 318; faults in cables, 

 405 ; final tests, 383 ; galvanic 

 polarization, 279; gutta-percha,' 284; 

 inductive capacity, 411 ; insulation, 

 299, 282 ; , loss of charge, 302 ; 

 Ohm's law, 256 ; place of fault, 378, 



