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.
---