Dry Pile

Dry Pile, in Electricity, is a battery in which the liquid is replaced by some such substance as paper or leather that will absorb sufficient moisture to assist the chemical action. Instead of using a few cells, many hundreds are ranged one on the other in a column. In Zamboni's dry pile each cell consists simply of a disc of paper about one inch in diameter, silvered or tinned on one side and coated with a thin layer of black manganese oxide on the other. From one to two thousand of these are piled up so as to form a cylinder, which need not be greater than twelve inches in length. It is enclosed in a glass cylinder with a brass cap at each end making contact with the pile. Dry piles last for many years; they give no shock or spark, but