Cooley's Cyclopædia of Practical Receipts and Collateral Information in the Arts, Manufactures, Professions, and Trades..., Sixth Edition, Volume II

by Arnold James Cooley; Richard Vine Tuson

VOLTA′IC ELECTRICITY. Syn. Galvanic e., Galvanism, Voltaism. That branch of electrical science which has reference to the phenomena attendant on the development of electricity by chemical action. Electricity thus developed may be made to show itself in the ‘static’ condition, so as to produce the effects of frictional electricity, but it is much more easily obtained in the ‘dynamic’ condition—in other words, as a ‘voltaic current’—when it is especially remarkable for its chemical and magnetic effects. If a plate of zinc and a plate of platinum be immersed in dilute sulphuric acid, and connected outside the liquid by a wire, a current of electricity will immediately be set up, and will continue as long as the conducting circuit is complete and the action of the acid on the zinc goes on. The current of ‘positive’ electricity passes from the zinc, through the liquid, to the platinum, and thence through the wire to the zinc. The arrangement of two dissimilar metals immersed in a liquid which acts upon one of them is called a voltaic couple. By uniting a number of couples together in regular order, a voltaic pile or battery is formed.

The older forms of the voltaic battery, viz., Volta’s pile, Cruikshank’s trough, and Wollaston’s battery, are now but little used. They all consist of a series of couples of zinc and copper, excited by an acid liquid, generally a mixture of water with ¹⁄₄₀th of its bulk of sulphuric acid, and ¹⁄₆₀th of nitric acid.

A. A copper cylinder, filled with a saturated solution of sulphate of copper.

B. A smaller porous cylinder (earthenware or membrane), containing a mixture of 1 measure of strong sulphuric acid, and about 8 measures of water.

C. A rod of amalgamated zinc, supported in the smaller cylinder by the cross-piece (i).

D. A shelf full of small holes, for supporting crystals of sulphate of copper, to keep up the strength of the solution.

e and f. Screws and caps to connect the wires g and h with the battery.

g. The negative wire, connected with the zinc.

h. The positive wire, connected with the copper.