Part 57

1748. It would be easy, on the same view, to explain hypothetically, how, if one of the rubbing bodies be a conductor, as the amalgam of an electrical machine, the state of the other when it comes from under the friction is (as a mass) exalted; but it would be folly to go far into such speculation before that already advanced has been confirmed or corrected by fit experimental evidence. I do not wish it to be supposed that I think all excitement by friction is of this kind; on the contrary, certain experiments lead me to believe, that in many cases, and perhaps in all, effects of a thermo-electric nature conduce to the ultimate effect; and there are very probably other causes of electric disturbance influential at the same time, which we have not as yet distinguished.

_Royal Institution. June, 1838._

INDEX.

* * * * *

N.B. A dash rule represents the _italics_ immediately preceding it. The references are sometimes to the individual paragraph, and sometimes to that in conjunction with those which follow.

* * * * *

_Absolute_ charge of matter, 1169. ---- quantity of electricity in matter, 852, 861, 873. Acetate of potassa, its electrolysis, 749. Acetates, their electrolysis, 774. Acetic acid, its electrolysis, 773. _Acid_, nitric, formed in air by a spark, 324. ----, or alkali, alike in exciting the pile, 932. ----, transference of, 525. ---- _for battery_, its nature and strength, 1128, 1137. ---- ----, nitric, the best, 1138. ---- ----, effect of different strengths, 1139. ---- _in voltaic pile_, does not evolve the electricity, 925, 933. ---- ----, its use, 925. Acids and bases, their relation in the voltaic pile, 927, 933.

## Active battery, general remarks on, 1034, 1136.

Adhesion of fluids to metals, 1038. Advantages of a new voltaic battery, 1132. _Affinities, chemical_, opposed voltaically, 891, 904, 910. ----, their relation in the active pile, 949. _Air_, its attraction by surfaces, 622. ----, _charge of_, 1173. ----, ----, by brush, 1434, 1441. ----, ----, by glow, 1537, 1543. ----, convective currents in, 1572, 1576, 1581. ----, dark discharge in, 1548. ----, disruptive discharge in, 1359, 1406, 1425, 1526. ----, induction in, 1208, 1215, 1284, 1362. ----, its insulating and conducting power, 411, 1332, 1336, 1362. ----, its rarefaction facilitates discharge, 1375. ----, electrified, 1443. ----, electro-chemical decompositions in, 454, 1623. ----, hot, discharges voltaic battery, 271, 274. ----, poles of, 455, 461, 559. ----, _positive and negative_ brush in, 1467, 1472, 1476. ----, ---- glow in, 1526, 1530. ----, ---- spark in, 1485. ----, rarefied, brush in, 1451, 1456. ----, retention of electricity on conductors by, 1377, 1398. ----, _specific inductive capacity of_, 1284. ----, ----, not varied by temperature or pressure, 1287, 1288. _Alkali_ has strong exciting power in voltaic pile, 884, 931, 941. ----, transference of, 525. _Amalgamated zinc_, its condition, 1000. ----, how prepared, 863. ----, its valuable use, 863, 999. ---- battery, 1001. _Ammonia_, nature of its electrolysis, 748. ----, solution of, a bad conductor, 554, 748. Ampère's inductive results, 78, 255, 379 _note_. _Anions_ defined, 665, 824. ----, table of, 847. ---- related through the entire circuit, 963. ----, their action in the voltaic pile, 924. ----, their direction of transfer, 962, Anode defined, 663. _Antimony_, its relation to magneto-electric induction, 139. ----, chloride of, not an electrolyte, 690, 796. ----, oxide of, how affected by the electric current, 801. ---- _supposed new_ protoxide, 693. ---- ----, sulphuret, 694. _Animal electricity_, its general characters considered, 351. ---- is identical with other electricities, 354, 360. ----, its chemical force, 355. ----, enormous amount, 359. ----, evolution of heat, 353, ----, magnetic force, 351. ----, physiological effects, 357. ----, spark, 358. ----, tension, 352. Apparatus, inductive, 1187. _See_ Inductive apparatus. _Arago's magnetic phenomena_, their nature, 81, 120. ----, reason why no effect if no motion, 126, ----, direction of motion accounted for, 121. ----, due to induced electric currents, 119, 248. ----, like electro-magnetic rotations in principle, 121. ----, not due to direct induction of magnetism, 128, 138, 215, 243, 248. ----, obtained with electro-magnets, 129. ----, produced by conductors only, 130, 215. ----, time an element in, 124. ----, Babbage and Hershel's results explained, 127. Arago's experiment, Sturgeon's form of, 219. Associated voltaic circles, 989. _Atmospheric_ balls of fire, 1611. ----, electricity, its chemical action, 336. Atomic number judged of from electrochemical equivalent, 851. _Atoms of matter_, 869, 1703. ----, their electric power, 856, 860. Attraction of particles, its influence in Döbereiner's phenomena, 619. _Attractions_, electric, their force, 1022 _note_. ----, _chemic, produce_ current force, 852, 918, 947, 996, 1741. ----, ---- local force, 852, 921, 947, 959, 1739. ----, hygrometric, 621. Aurora borealis referred to magneto-electric induction, 192. Axis of power, the electric current on, 517, 1627, 1642.

Balls of fire, atmospheric, 1611. Barlow's revolving globe, magnetic effects explained, 137, 160. Barry, decomposed bodies by atmospheric electricity, 338. Bases and acids, their relation in the pile, 927. Battery, Leyden, that generally used, 291. _Battery, voltaic_, its nature, 856, 989. ----, _origin of its power_, 878, 989. ----, ---- not in contact, 887, 915, ----, ---- chemical, 879, 916, 919, 1741. ----, ----, oxidation of the zinc, 919, 944. ----, its circulating force, 858, 1120. ----, its local force, 1120. ----, quantity of electricity circulating, 990. ----, intensity of electricity circulating, 990, 993. ----, _intensity of its current_, 909, 994. ----, ---- increased, 905, 989. ----, _its diminution in power_, 1035. ----, ---- _from_ adhesion of fluid, 1003, 1136. ----, ---- ---- peculiar state of metal, 1040. ----, ---- ---- exhaustion of charge, 1042. ----, ---- ---- irregularity of plates, 1045, 1146. ----, use of metallic contact in, 893, 896. ----, _electrolytes essential to it_, 921. ----, ----, why, 858, 923. ----, state of metal and electrolyte before contact, 916. ----, conspiring action of associated affinities, 989. ----, purity of its zinc, 1144. ----, use of amalgamated zinc in, 999. ----, _plates, their_ number, 1151. ----, ---- size, 1154. ----, ---- vicinity, 1148. ----, ---- immersion, 1150. ----, ---- relative age, 1146. ----, ---- foulness, 1145. ----, _excited by_ acid, 880, 926, 1137. ----, ---- alkali, 931, 934, 941. ----, ---- sulphuretted solutions, 943. ----, the acid, its use, 925, ----, acid for, 1128, 1137. ----, nitric acid best for, 1137. ----, construction of, 989, 1001, 1121. ----, with numerous alternations, 989. ----, Hare's, 1123. ----, general remarks on, 1031. 1136. ----, simultaneous decompositions with, 1156. ----, practical results with, 1136. ----, _improved_, 1001, 1006, 1120. ----, ----, its construction, 1124. ----, ----, power, 1125, 1128. ----, ----, advantages, 1132. ----, ----, disadvantages, 1132. Batteries, voltaic, compared, 1126. Becquerel, his important secondary results, 745, 784. Berzelius, his view of combustion, 870, 959. Biot's theory of electro-chemical decomposition, 486. Bismuth, its relation to magneto-electric induction, 139. _Bodies_ classed in relation to the electric current, 823. ---- classed in relation to magnetism, 255. Bodies electrolyzable, 824. Bonijol decomposed substances by atmospheric electricity, 336. Boracic acid a bad conductor, 408. _Brush, electric_, 1425. ----, produced, 1425. ----, not affected by nature of conductors, 1454, 1473. ----, is affected by the dielectrics, 1455, 1463, 1475. ----, not dependent on current of air, 1440. ----, proves molecular action of dielectric, 1449, 1450. ----, its analysis, 1427, 1433. ----, nature, 1434, 1441, 1447. ----, form, 1428, 1449, 1451. ----, _ramifications_, 1439. ---- ----, their coalescence, 1453. ----, sound, 1426, 1431. ----, requisite intensity for, 1446. ---- has sensible duration, 1437. ---- is intermitting, 1427, 1431, 1451. ----, _light of_, 1444, 1445, 1451. ----, ----, in different gases, 1446, 1454. ----, dark? 1444, 1552. ----, passes into spark, 1448. ----, spark and glow relation of, 1533, 1539, 1542. ----, in gases, 1454, 1463, 1476. ----, oxygen, 1457, 1476. ----, nitrogen, 1458, 1476. ----, hydrogen, 1459, 1476. ----, coal-gas, 1460, 1476. ----, carbonic acid gas, 1461, 1476. ----, muriatic acid gas, 1462, 1476. ----, rare air, 1451, 1455, 1474. ----, oil of turpentine, 1452. ----, positive, 1455, 1467, 1484. ----, _negative_, 1468, 1472, 1484. ----, ----, of rapid recurrence, 1468, 1491. ----, positive and negative in different gases, 1455, 1475, 1506.

_Capacity, specific inductive_, 1252. ----. _See_ Specific inductive capacity. _Carbonic acid gas_ facilitates formation of spark, 1463. ----, brush in, 1461, 1476. ----, glow in, 1534. ----, spark in, 1422, 1463. ----, _positive and negative_ brush in, 1476. ----, ---- discharge in, 1546. ----, non-interference of, 645, 652. Carbonic oxide gas, interference of, 645, 652. _Carrying discharge_, 1562. ----. _See_ Discharge convective. Cathode described, 663, 824. _Cations_, or cathions, described, 665, 824. ----, table of, 817. ----, direction of their transfer, 962. Cations, are in relation through the entire circuit, 963. _Characters of_ electricity, table of, 360. ---- the electric current, constant, 1618, 1627. ---- voltaic electricity, 268. ---- ordinary electricity, 284. ---- magneto-electricity, 343. ---- thermo-electricity, 349. ---- animal electricity, 351. _Charge_, free, 1684. ---- is always induction, 1171, 1177, 1300, 1682. ---- on surface of conductors: why, 1301. ----. _influence of_ form on, 1302. ----, ---- distance on, 1303. ----, loss of, by convection, 1569. ----, removed from good insulators, 1203. ---- of matter, absolute, 1169. ---- _of air_, 1173. ---- ---- by brush, 1434, 1441. ---- ---- by glow, 1526, 1537, 1543. ---- of particles in air, 1564. ---- of oil of turpentine, 1172. ---- of inductive apparatus divided, 1208. ----, residual, of a Leyden jar, 1249. ----, _chemical, for battery_, good, 1137. -----, ----, weak and exhausted, 1042, 1143. _Chemical action_, the, exciting the pile is oxidation, 921. ---- _superinduced by_ metals, 564. ---- ---- platina, 564, 617, 630. ---- tested by iodide of potassium, 315. Chemical actions, distant, opposed to each other, 891, 910, 1007. _Chemical affinity_ influenced by mechanical forces, 656. ---- transferable through metals, 918. ---- statical or local, 852, 921, 917, 959. ---- current, 852, 918, 947, 996. _Chemical decomposition by_ voltaic electricity, 278, 450, 661. ---- common electricity, 309, 453. ---- magneto-electricity, 346. ---- thermo-electricity, 349. ---- animal electricity, 355. ----. _See_ Decomposition electro-chemical. Chemical and electrical forces identical, 877, 918, 947, 960, 965, 1031. _Chloride of_ antimony not an electrolyte, 690. ---- _lead_, its electrolysis, 794, 815. ---- ----, electrolytic intensity for, 978. ---- _silver_, its electrolysis, 541, 813, 902. ---- ----, electrolytic intensity for, 979. ---- tin, its electrolysis, 789, 819. _Chlorides in_ solution, their electrolysis, 766. ---- fusion, their electrolysis, 789, 813. Circle of anions and cathions, 963. _Circles_, simple voltaic, 875. ----, associated voltaic, 989. Circuit, voltaic, relation of bodies in, 962. _Classification of bodies in relation to_ magnetism, 255. ---- the electric current, 823, 817. Cleanliness of metals and other solids, 633. _Clean platina_, its characters, 633, 717. ----, _its power of effecting combination_, 590, 605, 617, 632. ----, ----. _See_ Plates of platina. _Coal gas_, brush in, 1460. ----, dark discharge in, 1556. ----, positive and negative brush in, 1476. ----, positive and negative discharge in, 1515. ----, spark in, 1422. Colladon on magnetic force of common electricity, 289. Collectors, magneto-electric, 86. _Combination effected by_ metals, 564, 608. ---- solids, 564, 618. ---- poles of platina, 566. ---- _platina_, 564, 568, 571, 590, 630. ---- ----, as plates, 569. ---- ----, as sponge, 609, 636. ---- ----, cause of, 590, 616, 625, 656. ---- ----, how, 630. ---- ----, interferences with, 638, 652, 655. ---- ---- _retarded by_ olefiant gas, 640. ---- ---- ---- carbonic oxide, 645, 652. ---- ---- ---- sulphuret of carbon, 650. ---- ---- ---- ether, 651. ---- ---- ---- other substances, 649, 653, 654. Comparison of voltaic batteries, 1126, 1146. _Conditions_, general, of voltaic decomposition, 669. ----, new, of electro-chemical decomposition, 453. _Conducting power_ measured by a magnet, 216. ---- of solid electrolytes, 419. ---- of water, constant, 984. _Conduction_, 418, 1320. ----, its nature, 1320, 1326, 1611. ----, of two kinds, 987. ----, preceded by induction, 1329, 1332, 1338. ---- and insulation, cases of the same kind, 1320, 1326, 1336, 1338, 1561. ----, its relation to the intensity of the current conducted, 419. ---- common to all bodies, 444, 449. ---- by a vacuum, 1613. ---- by lac, 1234, 1324. ---- by sulphur, 1241, 1328. ---- by glass, 1239, 1324. ---- by spermaceti, 1240, 1323. ---- by gases, 1336. ----, slow, 1233, 1245, 1328. ---- affected by temperature, 445, 1339. ---- by metals diminished by heat, 432, 445. ---- increased by heat, 432, 441, 445. ---- of electricity and heat, relation of, 416. ----, _simple, can occur in electrolytes_, 967, 983. ----, ---- with very feeble currents, 970. ---- by electrolytes without decomposition, 968, 1017, 1032. ---- and decomposition associated in electrolytes, 413, 676, 854. ---- facilitated in electrolytes, 1355. ---- _by water_ bad, 1159. ---- ---- improved by dissolved bodies, 984, 1355. ----, electrolytic, stopped, 380, 1358, 1705. ---- of currents stopped by ice, 381. ---- conferred by liquefaction, 394, 410. ---- _taken away by solidification_, 394, 1705. ---- ---- why, 910, 1705. ----, _new law of_, 380, 394, 410. ----, ----, supposed exception to, 691, 1340. ----, general results as to, 443. Conductive discharge, 1320. _Conductors_, electrolytic, 474. ----, magneto-electric, 86. ----, their nature does not affect the electric brush, 1454. ----, size of, affects discharge, 1372. ----, form of, affects discharge, 1374, 1425. ----, _distribution of electricity on_, 1368. ----, ----, _affected by_ form, 1374. ----, ----, ---- distance, 1364, 1371. ----, ----, ---- air pressure, 1375. ----, ----, irregular with equal pressure, 1378. Constancy of electric current, 1618. _Constitution of electrolytes as to_ proportions, 679, 697, 830, 1708. ---- liquidity, 394, 823. _Contact of metals_ not necessary for electrolyzation, 879. ----, its use in the voltaic battery, 893. ---- not necessary for spark, 915, 956. _Contiguous particles_, their relation to induction, 1165, 1679. ---- active in electrolysis, 1349, 1703. _Convection_, 1562, 1642. ---- or convective discharge. _See_ Discharge convective. Copper, iron, and sulphur circle, 943. Coruscations of lightning, 1464. _Coulomb's electrometer_, 1180. ----, precautions in its use, 1182, 1186, 1206. Crystals, induction through, 1689. Cube, large, electrified, 1173. Cubes of crystals, induction through, 1692, 1695. Current chemical affinity, 852, 918, 947, 996. Current, voltaic, without metallic contact, 879, 887. _Current, electric_, 1617. ----, defined, 282, 511. ----, nature of, 511, 667, 1617, 1627. ----, variously produced, 1618. ----, _produced by_ chemical action, 879, 916, 1741. ----, ---- animals, 351. ----, ---- friction, 301, 307, 311. ----, ---- heat, 349, ----, ---- discharge of static electricity, 296, 307, 363. ----, ---- _induction by_ other currents, 6, 1089. ----, ---- ---- magnets, 30, 88, 344. ----, evolved in the moving earth, 181. ----, in the earth, 187. ----, natural standard of direction, 663. ----, none of one electricity, 1627, 1632, 1635. ----, two forces everywhere in it, 1627, 1632, 1635, 1642. ----, one, and indivisible, 1627. ----, an axis of power, 517, 1642. ----, constant in its characters, 1618, 1627. ----, inexhaustibility of, 1631. ----, _its velocity in_ conduction, 1648. ----, ---- electrolyzation, 1651. ----, regulated by a fine wire, 853, _note_. ----, affected by heat, 1637. ----, stopped by solidification, 381. ----, _its section_, 498, 504, 1634. ----, ---- presents a constant force, 1634. ----, _produces_ chemical phenomena, 1621. ----, ---- heat, 1625. ----, its heating power uniform, 1630. ----, produces magnetism, 1653. ----, Porrett's effects produced by, 1646. ----, _induction of_, 1, 6, 232, 241, 1101, 1048. ----, ----, on itself, 1048. ----, ----. _See_ Induction of electric current. ----, its inductive force lateral, 1108. ----, induced in different metals, 193, 213, 201, 211. ----, _its transverse effects_, 1653. ----, ---- constant, 1655. ----, _its transverse forces_, 1658. ----, ---- are in relation to contiguous particles, 1664. ----, ---- their polarity of character, 1665. ---- and magnet, their relation remembered, 38, _note_. _Currents_ in air by convection, 1572, 1581. ----, metals by convection, 1603. ----, oil of turpentine by convection, 1595, 1598. Curved lines, induction in, 1215. Curves, magnetic, their relation to dynamic induction, 217, 232.

Daniell on the size of the voltaic metals, 1525. _Dark discharge_,1444, 1544. ----. _See_ Discharge, dark. Dates of some facts and publications, 139, _note after_. _Davy's_ theory of electro-chemical decomposition, 482, 500. ---- electro-chemical views, 965. ---- mercurial cones, convective phenomena, 1603. _Decomposing force_ alike in every section of the current, 501, 505. ----, variation of, on each particle, 503. _Decomposition_ and conduction associated in electrolytes, 413, 854. ----, primary and secondary results of, 742, 777. ---- _by common electricity_, 309, 454. ---- ----, precautions, 322. _Decomposition, electro-chemical_, 450, 669. ----, nomenclature of, 661. ----, new terms relating to, 662. ----, its distinguishing character, 309. ----, by common electricity, 309, 454. ----, by a single pair of plates, 862, 897, 904, 931. ----, by the electric current, 1621. ----, without metallic contact, 880, 882. ----, its cause, 891, 904, 910. ----, not due to direct attraction or repulsion of poles, 493, 497, 536, 542, 5460. ----, _dependent on_ previous induction, 1345. ----, ---- the electric current, 493, 510, 524, 854. ----, ---- intensity of current, 905. ----, ---- chemical affinity of particles, 519, 525, 519. ----, resistance to, 891, 910, 1007. ----, intensity requisite for, 966, 1354. ----, stopped by solidification, 380, 1358, 1705. ----, retarded by interpositions, 1007. ----, assisted by dissolved bodies, 1355. ----, division of the electrolyte, 1347, 1623, 1701. ----, transference, 519, 525, 538, 550, 1347, 1706. ----, why elements appear at the poles, 535. ----, uncombined bodies do not travel, 544, 546. ----, circular series of effects, 562, 962. ----, simultaneous, 1156, ----, _definite_, 329, 372, 377, 504, 704, 714, 722, 726, 732, 764, 783, 807, 821, 960. ----, ---- independent of variations of electrodes, 714, 722, 807, 832. ----, necessary intensity of current, 911, 966, 1345, 1354. ----, influence of water in, 472. ----, in air, 451, 461, 469. ----, some general conditions of, 669. ----, new conditions of, 453. ----, primary results, 742. ----, secondary results, 702, 742, 748, 777. ----, of acetates, 774. ----, acetic acid, 773. ----, ammonia, 748. ----, _chloride of_ antimony, 690, 796. ----, ---- lead, 794, 815. ----, ---- silver, 541, 813, 979. ----, _chlorides in_ solution, 766. ----, ---- fusion, 789, 913. ----, fused electrolytes, 789. ----, hydriodic acid and iodides, 767, 787. ----, hydrocyanic acid and cyanides, 771. ----, hydrofluoric acid and fluorides, 770. ----, _iodide of_ lead, 802, 818. ----, ---- potassium, 805. ----, muriatic acid, 758, 780. ----, nitre, 753. ----, nitric acid, 752. ----, _oxide_ antimony, 801. ----, ---- lead, 797. ----, protochloride of tin, 789, 819. ----, protiodide of tin, 804. ----, sugar, gum, &c., 776. ----, of sulphate of magnesia, 495. ----, sulphuric acid, 757. ----, sulphurous acid, 755. ----, tartaric acid, 775. ----, water, 704, 785, 807. ----, _theory of_, 477, 1345. ----, ----, by A. de la Rive, 489, 507, 514, 543. ----, ----, Biot, 486. ----, ----, Davy, 482, 500. ----, ----, Grotthuss, 481, 499, 515. ----, ----, Hachette, 491, 513, ----, ----, Riffault and Chompré, 485, 507, 512. ----, author's theory, 518, 524, 1345, 1623, 1703, 1766. _Definite_ decomposing action of electricity, 329, 372, 377, 504, 704, 783, 821. ----, magnetic action of electricity, 216, 362, 367, 377. ----, _electro-chemical action_, 822, 869, 960. ----, ----, general principles of, 822, 862. ----, ----, _in chloride of lead_, 815. ----, ----, ---- silver, 813. ----, ----, in hydriodic acid, 767, 787. ----, ----, iodide of lead, 802, 818. ----, ----, muriatic acid, 758, 786, ----, ----, protochloride of tin, 819. ----, ----, water, 732, 785, 807. Degree in measuring electricity, proposal for, 736. _De la Rive_ on heat at the electrodes, 1637. ----, his theory of electro-chemical decomposition, 489, 507, 514, 543. _Dielectrics_, what, 1168. ----, their importance in electrical actions, 1666. ----, their relation to static induction, 1296. ----, their condition under induction, 1369, 1679. ----, their nature affects the brush, 1455. ----, their specific electric actions, 1296, 1398, 1423, 1454, 1503, 1560. Difference of positive and negative discharge, 1465, 1480, 1485. Differential inductometer, 1307. _Direction of_ ions in the circuit, 962. ----, the electric current, 563. ----, the magneto-electric current, 114, 116. ----, the induced volta-electric current, 19, 26, 1091. Disruptive discharge, 1359, 1405. _See_ Discharge, disruptive. _Discharge, electric_, as balls of fire, 1641. ----, of Leyden jar, 1300. ----, _of voltaic battery by_ hot air, 271, 274. ----, ---- points, 272. ----, velocity of, in metal, varied, 1333. ----, varieties of, 1319. ----, brush, 1425. _See_ Brush. ----, carrying, 1562. _See_ Discharge, convective. ----, conductive, 1320. _See_ Conduction. ----, dark, 1444, 1544. ----, disruptive, 1359, 1405. ----, electrolytic, 1343, 1622, 1704. ----, glow, 1526. _See_ Glow. ----, positive and negative, 1465. ----, spark, 1406. _See_ Spark, electric. _Discharge, connective_, 1442, 1562, 1601, 1623, 1633, 1642. ----, in insulating media, 1562, 1572. ----, in good conductors, 1603. ----, _with fluid terminations in_ air, 1581, 1589. ----, ---- liquids, 1597. ----, from a ball, 1576, 1590. ----, influence of points in, 1573. ----, _affected by_ mechanical causes, 1579. ----, ---- flame, 1580. ----, with glow, 1576. ----, _charge of a particle in_ air, 1564. ----, ---- oil of turpentine, 1570. ----, charge of air by, 1442, 1592. ----, _currents produced in_ air, 1572, 1581, 1591. ----, ---- oil of turpentine, 1595, 1598. ----, direction of the currents, 1599, 1645. ----, Porrett's effects, 1646, ----, positive and negative, 1593, 1600, 1643. ----, related to electrolytic discharge, 1622, 1633. _Discharge, dark_, 1444, 1544, 1560. ----, with negative glow, 1544. ----, between positive and negative glow, 1547. ----, in air, 1548. ----, muriatic acid gas, 1554. ----, coal gas, 1556. ----, hydrogen, 1558. ----, nitrogen, 1559. _Discharge, disruptive_, 1405. ----, preceded by induction, 1362. ----, determined by one particle, 1370, 1409. ----, necessary intensity, 1409, 1553. ----, determining intensity constant, 1410. ----, related to particular dielectric, 1503. ----, facilitates like action, 1417, 1435, 1453, 1553. ----, its time, 1418, 1436, 1498, 1641. ----, _varied by_ form of conductors, 1302, 1372, 1374. ----, ---- change in the dielectric, 1395, 1422,1454. ----, ---- rarefaction of air, 1365, 1375, 1451. ----, ---- temperature, 1367, 1380. ----, ---- distance of conductors, 1303, 1364, 1371. ----, ---- size of conductors, 1372. ----, in liquids and solids, 1403. ----, in _different gases_, 1381, 1388, 1421. ----, ---- not alike, 1395. ----, ---- specific differences, 1399, 1422, 1687. ----, _positive and negative_, 1393, 1399, 1465, 1524. ----, ----, distinctions, 1467, 1475, 1482. ----, ----, differences, 1485, 1501. ----, ----, relative facility, 1496, 1520. ----, ----, dependent on the dielectric, 1503. ----, ----, in different gases, 1506, 1510, 1518, 1687. ----, ----, of voltaic current, 1524. ----, brush, 1425. ----, collateral, 1412. ----, dark, 1444, 1544, 1560. ----, glow, 1526. ----, spark, 1406. ----, theory of, 1308, 1406, 1434. _Discharge, electrolytic_, 1164, 1343, 1621, 1703, 1706. ----, previous induction, 1345, 1351. ----, necessary intensity, 912, 966, 1346, 1354. ----, division of the electrolyte, 1347, 1704. ----, stopped by solidifying the electrolyte, 380, 1358, 1705. ----, facilitated by added bodies, 1355. ----, in curved lines, 521, 1216, 1351. ----, proves action of contiguous particles, 1349. ----, positive and negative, 1525. ----, velocity of electric current in, 1650. ----, related to convective discharge, 1622. ----, theory of, 1344, 1622, 1704. Discharging train generally used, 292. Disruptive discharge, 1405. _See_ Discharge, disruptive. Dissimulated electricity, 1684. _Distance, its influence_ in induction, 1303, 1364,1371. ---- over disruptive discharge, 1364, 1371. Distant chemical actions, connected and opposed, 891, 909. Distinction of magnetic and magneto-electric action, 138, 215, 243, 253. Division of a charge by inductive apparatus, 1208. Döbereiner on combination effected by platina, 609, 610. Dulong and Thenard on combination by platina and solids, 609, 611. Dust, charge of its particles, 1567.