Particles, their nascent state, 658. —— in air, how charged, 1564. ——, neighbouring, their relation to each other, 619, 624, 657. ——, contiguous, active in induction, 1165, 1677. —— of a dielectric, their inductive condition, 1369, 1410, 1669. ——, polarity of, when under induction, 1298, 1676. ——, how polarised, 1669, 1679. ——, ——, in any direction, 1689. ——, ——, as wholes or elements, 1699. ——, ——, in electrolytes, 1702. ——, crystalline, 1689. ——, contiguous, active in electrolysis, 1349, 1702. ——, their action in electrolyzation, 520, 1343, 1703. ——, —— local chemical action, 961, 1739. ——, —— relation to electric action, 73. ——, —— electric action, 1669, 1679, 1740. Path of the electric spark, 1107. Phosphoric acid not an electrolyte, 682. Physiological effects of voltaic-electricity, 279. —— common electricity, 332. —— magneto-electricity, 56, 347. —— thermo-electricity, 349. —— animal electricity, 357. Pile, voltaic, electricity of, 875. ——. See Battery, voltaic. Plates of platina effect combination, 568, 571, 590, 630. —— prepared by electricity, 570, 585, 588. —— —— friction, 591. —— —— heat, 595. —— —— chemical cleansing, 599, 605, ——, clean, their general properties, 633, 717. ——, their power preserved, 576. ——, —— in water, 580. ——, their power diminished by action, 581. ——, —— exposure to air, 636. ——, their power affected by washing in water, 582. ——, —— heat, 584, 597. ——, —— presence of certain gases, 638, 655. ——, their power, cause of, 590, 616, 630. ——, theory of their action, Doebereiner's, 610. ——, ——, Dulong and Thenard's, 611. ——, ——, Fusinieri's, 613. ——, ——, author's, 619, 626, 630, 656. Plates of voltaic battery foul, 1145. ——, new and old, 1116. ——, vicinity of, 1148. ——, immersion of, 1003, 1150. ——, number of, 989, 1151. ——, large or small, 1154. Platina, clean, its characters, 633, 717. —— attracts matter from the air, 634. ——, spongy, its state, 637. ——, clean, its power of effecting combination, 564, 590, 605, 617, 630. ——, —— interfered with, 638. ——, its action retarded by olefiant gas, 640, 652. ——, ——, carbonic oxide, 645, 652. ——. See Combination, Plates of platina, and Interference. —— poles, recombination effected by, 567, 588. Plumbago poles for chlorides, 794. Poisson's theory of electric induction, 1305. Points, favour convective discharge, 1573. ——, fluid for convection, 1581. Polar forces, their character, 1665. —— decomposition by common electricity, 312, 321, 469. Polarity, meaning intended, 1304, 1685. —— of particles under induction, 1298, 1676. ——, electric, 1070, 1085. ——, ——, its direction, 1688, 1703, ——, ——, its variation, 1687. ——, ——, its degree, 1686. ——, ——, in crystals, 1689. ——, ——, in molecules or atoms, 1699. ——, ——, in electrolytes, 1702. Polarized light across electrolytes, 951. Poles, electric, their nature, 461, 498, 556, 662. ——, appearance of evolved bodies at, accounted for, 535. —— one element to either? 552, 681, 757. ——, of air, 455, 461, 559. ——, of water, 491, 558. ——, of metal, 557. ——, of platina, recombination effected by, 567, 588. ——, of plumbago, 794. Poles, magnetic, distinguished, 44, note. Porrett's peculiar effects, 1646. Positive current none, 1627, 1632. —— discharge, 1465, 1480. —— ——, as spark, 1467, 1482. —— ——, as brush, 1467, 1476. —— spark or brush, 1484, 1502. —— and negative, convective discharge, 1600. —— —— disruptive discharge, 1465, 1482, 1485, 1525. —— —— —— in different gases, 1393. —— —— voltaic discharge, 1524. —— —— electrolytic discharge, 1525. Potassa acetate, nature of its electrolysis, 749. Potassium, iodide of, electrolysed, 805. Power of voltaic batteries estimated, 1126. Powers, their state of tension in the pile, 949. Practical results with the voltaic battery, 1136. Pressure of air retains electricity, explained, 1377, 1398. Primary electrolytical results, 742. Principles, general, of definite electrolytic action, 822. Proportionals in electrolytes, single, 679, 697.

Quantity of electricity in matter, 852, 861, 873, 1652. —— voltaic battery, 990.

Rarefaction of air facilitates discharge, why, 1375. Recombination, spontaneous, of gases from water, 566. Relation, by measure, of electricities, 361. —— of magnets and moving conductors, 256. —— of magnetic induction to intervening bodies, 1662, 1728. —— of a current and magnet, to remember, 38, note. —— of electric and magnetic forces, 118, 1411, 1653, 1658,1709, 1731. —— of conductors and insulators, 1321, 1326, 1334, 1338. —— of conduction and induction, 1320, 1337. —— of induction and disruptive discharge, 1362. —— —— electrolyzation, 1164, 1343. —— —— excitation, 1178, 1740. —— —— charge, 1171, 1177, 1300. —— of insulation and induction, 1324, 1362, 1368, 1678. ——, lateral, of lines of inductive force, 1231, 1297, 1304. —— of a vacuum to electricity, 1613. —— of spark, brush, and glow, 1533, 1539, 1542. —— of gases to positive and negative discharge, 1510. —— of neighbouring particles to each other, 619, 624. —— of elements in decomposing electrolytes, 923, 1702. —— —— exciting electrolytes, 921. —— of acids and bases voltaically, 927, 933. Remarks on the active battery, 1034, 1136. Residual charge of a Leyden jar, 1249. Resistance to electrolysis, 891, 904, 911, 1007. —— of an electrolyte to decomposition, 1007. Results of electrolysis, primary or secondary, 742, 777. ——, practical, with the voltaic battery, 1136. ——, general, as to induction, 1295, 1669. Retention of electricity by pressure of the atmosphere explained, 1377, 1398. Revolving plate. See Arago's phenomena. —— globe, Barlow's, effect explained, 137, 160, 169. —— ——, magnetic, 164. —— ——, direction of currents in, 161, 166. Riffault's and Chompre's theory of electro-chemical decomposition, 485, 507, 512. Rock crystal, induction across, 1692. Room, insulated and electrified, 1173. Rotation of the earth a cause of magneto-electric induction, 181.

Salts considered as electrolytes, 698. Scale of electrolytic intensities, 912. Secondary electrolytical results, 702, 742, 748, 777. —— become measures of the electric current, 843. Sections of the current, 498, 1634. ——, decomposing force alike in all, 501, 1621. Sections of lines of inductive action, 1369. ——, amount of force constant, 1369. Shock, strong, with one voltaic pair, 1049. Silver, chloride of, its electrolyzation, 541, 813, 902. ——, electrolytic intensity for, 979. Silver, sulphuret of, hot, conducts well, 433. Simple voltaic circles, 875. ——, decomposition effected by, 897, 904, 931. Single and many pairs of plates, relation of, 990. Single voltaic circuits, 875. —— without metallic contact, 879. —— with metallic contact, 893. —— their force exalted, 906. —— give strong shocks, 1049. —— —— a bright spark, 1050. Solid electrolytes are non-conductors, 394, 402, 1358. ——, why, 910, 1705. Solids, their power of inducing combination, 564, 618. —— interfered with, 638. Solubility of gases in cases of electrolyzation, 717, 728. Source of electricity in the voltaic pile, 875. —— is chemical action, 879, 916, 919, 1741. Spark, 1360, 1406. Spark, electric, its conditions, 1360, 1406, 1553. —— path, 1407. —— light, 1553. —— insensible duration or time, 1438. —— accompanying dark parts, 1547, 1632. —— determination, 1370. 1409. Spark is affected by the dielectrics, 1395, 1421. —— size of conductor, 1372. —— form of conductor, 1302, 1374. —— rarefaction of air, 1375. Spark, atmospheric or lightning, 1464, 1641. ——, negative, 1393, 1467, 1482, 1484, 1502. ——, positive, 1393, 1448, 1467, 1482, 1484, 1502. ——, ragged, 1420, 1448. ——, when not straight, why, 1568. ——, variation in its length, 1381. ——, tendency 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. ——, ——, —— with a magnet, 147. ——, —— a single wire, 170. ——, —— a revolving plate, 149. ——, —— a revolving ball, 160. ——, —— the earth, 173. Test between magnetic and magneto-electric action, 215, 243. Theory of combination of gases by clean platina, 619, 626, 630, 656. —— electro-chemical decomposition, 477, 661, 1623, 1704. —— the voltaic apparatus, 875, 1741. —— static induction, 1165, 1231, 1295, 1666, 1667. —— disruptive discharge, 1368, 1406, 1434. —— Arago's phenomena, 120. Thermo-electricity, its general characters, 349. —— identical with other electricities, 360. ——, its evolution of heat, 349. ——, magnetic, force, 349. ——, physiological effects, 349. ——, spark, 349. Time, 59, 68, 124, 1248, 1328, 1346, 1418, 1431, 1436, 1439, 1612, 1641, 1730. Tin, iodide of, electrolysed, 804. ——, protochloride, electrolysis of, definite, 789, 819. Torpedo, nature of its electric discharge, 359. ——, its enormous amount of electric force, 359. Transfer of elements and the current, their relation, 923, 962. Transference is simultaneous in opposite directions, 542, 828. ——, uncombined bodies do not travel, 544, 546, 826. —— of elements, 454, 507, 539, 550, 826. —— —— across great intervals, 455, 468. —— ——, its nature, 519, 525, 538, 549. —— of chemical force, 918. Transverse forces of the current, 1653, 1709. Travelling of charged particles, 1563. Trough, voltaic. See Battery, voltaic. Turpentine, oil of, a good fluid insulator, 1172. ——, its insulating power destroyed, 1571. —— charged, 1172. ——, brush in, 1452, ——, electric motions in, 1588, 1595, ——, convective currents in, 1595, 1598.

Unipolarity, 1635.

Vacuum, its relation to electricity, 1613. Vaporization, 657. Velocity of conduction in metals varied, 1333. —— the electric discharge, 1641, 1649. —— conductive and electrolytic discharge, difference of, 1650. Vicinity of plates in voltaic battery, 1148. Volta-electric induction, 26. Volta-electrometer, 704, 736. ——, fluid decomposed in it, water, 706, 728, 732. ——, forms of, 707, 734. —— tested for variation of electrodes, 714, 722. —— —— fluid within, 727. —— —— intensity, 723. ——, strength of acid used in, 728,733. ——, its indications by oxygen and hydrogen, 736. ——, —— hydrogen, 734. ——, —— oxygen, 735. ——, how used, 737. Voltameter, 704. Voltaic battery, its nature, 875, 989. ——, remarks on, 1034, 1136. ——, improved, 1001, 1119. ——, practical results with, 1136. ——. See Battery, voltaic. Voltaic circles, simple, 875. ——, decomposition by, 897. Voltaic circles associated, or battery, 989. Voltaic circuit, relation of bodies in, 962. ——, defined, 282, 511. ——, origin of, 916, 1741. ——, its direction, 663, 925, ——, intensity increased, 905, 990. ——, produced by oxidation of zinc, 919, 930. —— not due to combination of oxide and acid, 925, 933. ——, its relation to the combining oxygen, 921, 962. ——, —— combining sulphur, 943. ——, —— the transferred elements, 923, 962. ——, relation of bodies in, 962. Voltaic current, 1617. See Current, electric. Voltaic discharge, positive and negative, 1524. Voltaic decomposition, 450, 600. See Decomposition, electro-chemical. Voltaic electricity, identical with electricity, otherwise evolved, 268, 360. ——, discharged by points, 272. ——, —— hot air, 271, 274. ——, its tension, 268, 275. ——, evolution of heat by, 276. ——, its magnetic force, 277. ——, its chemical force, 278. ——, its spark, 280. ——, its physiological effects, 279. ——, its general characters considered, 268. Voltaic pile distinguished, 856, note. ——, electricity of, 875. ——, depends on chemical action, 872. ——, relation of acid and bases in the, 927. ——. See Battery, voltaic. Voltaic spark without contact, 915, 956. ——, precautions, 958, 1074. Voltaic trough, 989. See Battery, voltaic.

Water, flowing, electric currents in, 190. ——, retardation of current by, 1159. ——, its direct conducting power, 1017, 1159, 1355. ——, —— constant, 984. ——, electro-chemical decomposition against, 494, 532. ——, poles of, 494, 533, 558. ——, its influence in electro-chemical decomposition, 472. —— is the great electrolyte, 924. ——, the exciting electrolyte when pure, 944. ——, —— acidulated, 880, 926, 1137. ——, —— alkalized, 931, 934, 941. ——, electrolytic intensity for, 968, 981, 1017. —— electrolyzed in a single circuit, 862. ——, its electrolysis definite, 732, 785, 807. ——, decomposition of by fine wires, 327. ——, quantity of electricity in its elements, 853, 861. ——, determined to either pole, 553. Wheatstone's analysis of the electric brush, 1427. —— measurement of conductive velocity in metals, 1328. Wire, ignition of, by the electric current, 853, note, 1631. —— is uniform throughout, 1630. Wire a regulator of the electric current, 853, note. ——, velocity of conduction in, varied, 1333. ——, single, a current induced in, 170. ——, long, inductive effects in, 1064, 1118. Wollaston on decomposition by common electricity, 309. —— decomposition of water by points, 327.

Zinc, amalgamated, its condition, 863, 1000. ——, used in pile, 999. Zinc, how amalgamated, 863. ——, of troughs, its purity, 1144. ——, its relation to the electrolyte, 949. ——, its oxidation is the source of power in the pile, 919. —— plates of troughs, foul, 1145. —— ——, new and old, 1146. ——, waste of, in voltaic batteries, 997.

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