INDEX. 



427 



Marie Davy's battery, 229. 



MattMessen, correction formula, 331 ; 

 alloy unit, 338 ; copper resistance, 

 356 ; effects of temperature, 267. 



Measurements of conductor, 353 ; elec- 

 tro-inotive force, 305; Fechner's 

 method, 317 ; Wheatstone's method, 

 319 ; Ohm's method, 320 ; Poggen- 

 dorff's, 320 ; of galvanic current, 

 232 ; of charge, 301 ; of discharge, 

 301 ; of galvanic constants, 303. 



Mechanical effect, 333. 



Meidinger's element, 224. 



Meissner's lightning-guard, 207. 



Mercury unit, 328. 



Metals, conducting power, 266 ; elec- 

 tric permanency, 373. 



Morse's, chemical telegraph, 41 ; elec- 

 tro-magnetic telegraph, 41 ; trans- 

 mitting key, 41 ; simple circuit, 84 ; 

 transmitting plate, 90 ; apparatus 

 with relay, 92 ; for two stations, 93 ; 

 with induction currents, 131 ; with 

 closed circuit, 148. 



Multiplier, 22. 



Musschenbrceck, 3. 



Needle instruments, 46 ; magnetic, 21. 

 Negative electricity, 3. 

 Nottebohn\'s commutator, 96 ; light- 

 ning-guard, 210. 



Ocean telegraphy, 341. 

 Oerstedt, 21. 



Ohm's law, 256 ; method, 330. 

 Operations during paying out, 391. 

 Origin of galvanic currents, 215. 

 Ostend-Dover cable, 341. 

 Overland lines, 185 ; erection of, 198 ; 

 charge in, 200. 



Parallel lines, 288. 



Paying out cables, 391. 



Physiological effects, 219; telegraph, 

 219. 



Pile, voltaic, 17. 



Polarized relay, 133; with recorders, 

 138. 



Positive electricity, 3. 



Posts, erection of, 198 ; impregnation 

 of, 185; iron, 188; stone, 187; 

 wooden, 185. 



Pouillet's, tangent galvanometer, 239. 



Pressure tests, 351. 



Printing telegraphs, 165 ; Bain's, 176 ; 

 Bakewell's, 179 ; House's, 53 ; Sie- 

 mens', 50 ; Hughes', 55. 



Progress in cable tests, 357 ; insula- 

 tion, 358. 



Quantity, electrical, 333. 



Railway telegraphs, 65. 



Rate of working, 419. 



Red Sea cable, 345. 



Reid's pressure tanks, 351. 



Relay, apparatus with, 92 ; Morse's, 

 42; polarized, 133; Wheatstone's, 

 40. 



Repulsion, 2. 



Resinous electricity, 3. 



Resistance, boxes, 253 ; column, 255 ; 

 galvanic elements, 313; absolute, 

 336 ; of conductors, 353, 355 ; of 

 core, 356 ; of cables, 353 ; under 

 pressure, 365, 366 ; thermometer, 

 374. 



Reusser's telegraph, 9 ; alarm, 10. 



Rhepstat, 251 ; Jacobi's, 252 ; Poggen- 

 dorff's, 253. 



Ritchie's telegraph, 23. 



Ronald's telegraph, 10. 



Rupture of conductors, 379 ; De Sauty's 

 method, 379 ; Varley's method, 381. 



Salva's telegraph, 10. 

 Sand batteries, 228. 

 Schilling's telegraph, 27. 

 Schweiger's telegraph, 20 ; multiplier, 

 22. 



Sections.^ Cable, new Atlantic, 349 ; 

 Dover- Calais, 342 ; Dover- Ostend, 

 342 ; old Atlantic, 343 ; shore end, 

 343 ; Red Sea, 343 ; shore end, 343 ; 

 Malta, 345 ; Carthagena, 347 ; sec- 

 tions of bottom, 292. 



Self-acting make and break, 51. 



Self-heating of cables, 373. 



Ship's galvanometer, 390. 



Shunt circuits, 286. 



Siemens' self-acting make and break, 

 51 ; pointer telegraph, 76 ; commu- 

 tator, 98 ; submarine key, 113 ; 

 direct working instrument, 125 ; 

 polarized recorder, 138; type tele- 

 graph, 166 ; lightning discharger, 

 208 ; "iron posts, 188 ; apparatus 

 for testing, 294 ; resistance scales, 

 243 ; unit, 328 ; wippe, 415. 



Sine galvanometer, 241 ; tangent gal- 

 vanometer, 246. 



Single needle telegraph, 46. 



Slack, 395. 



Smith, Willoughby, cable testing, 400. 



Scemmering's telegraph, 18. 



Sounder, 146. 



Soundings, 392. 



Spark, 2. 



Specific conducting powers, 264. 



