to its repetition, 1392. ——­, facilitates discharge, 1417, 1553. ——­, passes into brush, 1448. ——­, preceded by induction, 1362. ——­, forms nitric acid in air, 324. ——­, in gases, 1383, 1421. ——­, in air, 1422. ——­, in nitrogen, 1422, 1463. ——­, in oxygen, 1422. ——­, in hydrogen, 1422. ——­, in carbonic acid, 1422, 1463. ——­, in muriatic acid gas, 1422, 1463. ——­, in coal-gas, 1422. ——­, in liquids, 1424. ——­, precautions, 958, 1074. ——­, voltaic, without metallic contact, 915, 956. ——­ from single voltaic pair, 1050. ——­ from common and voltaic electricity assimilated, 334. ——­, first magneto-electric, 32. ——­ of voltaic electricity, 280. ——­ of common electricity, 333. ——­ of magneto-electricity, 348. ——­ of thermo-electricity, 349. ——­ of animal electricity, 358. ——­, brush and glow related, 1533, 1539, 1542.  Sparks, their expected coalition, 1412.  Specific induction. See Induction, specific, 1252. Specific inductive capacity, 1252. ——­, apparatus for, 1187. ——­ of lac, 1256, 1270, 1308. ——­ of sulphur, 1275, 1310. ——­ of air, 1284. ——­ of gases, 1283, 1290. ——­ of glass, 1271. Spermaceti, its conducting power, 1240, 1323. ——­, its relation to conduction and insulation, 1322.  Standard of direction in the current, 663.  State, electrotonic, 60, 231, 242, 1114, 1661, 1729.  Static induction. See Induction, static. Sturgeon, his form of Arago’s experiment, 249. ——­, use of amalgamated zinc by, 863, 999. Sulphate of soda, decomposed by common electricity, 317. ——­, electrolytic intensity for, 975. Sulphur determined to either pole, 552, 681, 757. ——­, its conducting power, 1241, 1245. ——­, its specific inductive capacity, 1275. ——­, copper and iron, circle, 943. Sulphuret of carbon, interference of, 650. ——­ silver, hot, conducts well, 433.  Sulphuretted solution excites the pile, 943. Sulphuric acid, conduction by, 409, 681. ——­, magneto-electric induction on, 200, 213. ——­ in voltaic pile, its use, 925. ——­ not an electrolyte, 681. ——­, its transference, 525. ——­, its decomposition, 681, 757.  Sulphurous acid, its decomposition, 755. Summary of conditions of conduction, 443. ——­ molecular inductive theory, 1669.

Table of discharge in gases, 1388. ——­ electric effects, 360. ——­ electro-chemical equivalents, 847. ——­ electrolytes affected by fusion, 402. ——­ insulation in gases, 1388. ——­ ions, anions, and cathions, 847.  Tartaric acid, nature of its electrolysis, 775. Tension, inductive, how represented, 1370. ——­ of voltaic electricity, 268. ——­ of common electricity, 285. ——­ of thermo-electricity, 349. ——­ of magneto-electricity, 343. ——­ of animal electricity, 352. ——­ of zinc and electrolyte in the voltaic pile, 949.  Terrestrial electric currents, 187. Terrestrial magneto-electric induction, 140. ——­ cause of aurora borealis, 192. ——­, electric currents produced by, 141, 150. ——­, ——­, in helices alone, 148. ——­, ——­, ——­ with iron, 141, 146. ——­, ——­,