Cell Electric

Cell, Electric. In Electricity the cell means each separate element of a battery (q.v.). The following are the more important cells, with their composition and electro-motive force (E.M.F.): -

(A) Simple cells: Volta, zinc and copper in dilute sulphuric acid ; E.M.F. .8 - 1.04 volts, but inconstant. Smee, zinc and platinised silver in dilute sulphuric acid; E.M.F. .7 volts, and polarisation partly remedied. Bichromate, zinc and carbon in a solution of bichromate of potash and sulphuric acid; E.M.F. 2.3 - 1.7 volts.

(B) Compound Cells: Danieil, zinc in dilute sulphuric acid, or zinc sulphate, copper in saturated solution of copper sulphate; E.M.F. about 1.1 volts and constant. Grove, zinc in sulphuric acid, platinum in strong nitric acid; E.M.F. about 1.9 volts and constant; resistance low. Bunsen, similar to the Grove cell, but with carbon stick in place of the platinum. Leclanche, zinc in solution of sal-ammoniac, carbon stick imbedded in a mixture of powdered charcoal and black manganese-oxide; E.M.F. about 1.5 volts, diminishing rapidly when in use, but recovering if left to itself; very little attention required. De la Rue, zinc in chloride of zinc solution, silver in fused silver chloride; E.M.F. 1.046 volts and quite constant. Latimer Clark's Standard Cell, mercury and zinc with mercurous sulphate paste; E.M.F. 1.436 volts.

(C) Secondary Cells: Grove's Gas Battery, platinum electrodes in dilute sulphuric acid with hydrogen and oxygen gas evolved at the two poles; E.M.F. 1.47 volts. Plante, lead electrodes in dilute sulphuric acid, with surfaces specially prepared by repeated charges in alternate directions; modifications by Faure, Sellon, and others; E.M.F. 2.22 - 1.96 volts; resistance extremely low.