——­, 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