"To avoid all loss of silver I cover the carbon with asbestos paper, or
with cloth of the same material, d. My piles are arranged in ebonite
vessels, A, which are flat, as in Fig. 1, or round, as in Fig. 2.

"In Fig 1 there is seen, at e, gutta-percha separating the zinc from the
carbon at the base.

"Under such conditions, we obtain a powerful couple that possesses an
electro-motive power of 1.5 to 1.8 volts, according to the concentration
of the exciting liquid. The internal resistance is extremely feeble. I
have obtained with piles arranged like those shown in the figures nearly
0.06 ohm, the measurements having been taken from a newly charged pile.

"When the element is used up, and, notably, when all the chloride of
silver is reduced, it is only necessary to plunge the carbon with its
asbestos covering (after washing it in water) into a chloridizing bath,
in order to bring back the metallic silver that invests the carbon to a
state of chloride, and thus restore the pile to its primitive energy.
After this the carbon is washed and put back into the exciting liquid.

"These reductions of the chloride of silver during the operation of the
pile can be reproduced _ad infinitum_, since they are accompanied by no
loss of metal. The alkaline liquid is sufficient in quantity for two
successive charges of the couple.

"The chloridizing bath consists of 100 parts of acetic acid, 5 to 6
parts, by weight, of hydrochloric acid, and about 30 parts of water.

[Illustration: FIG. 1.--SCRIVANOW'S CHLORIDE OF SILVER PILE.]