ates 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, 1