however, being that the storing capacity was not sufficient as compared
with the weight and size of the cell. This difficulty has now been
overcome by M. Faure; the cell as he has improved it is made in the
following manner:

The two strips of lead are separately covered with minium or some other
insoluble oxide of lead, then covered with an envelope of felt, firmly
attached by rivets of lead. These two electrodes are then placed near
each other in water acidulated with sulphuric acid, as in the Plante
cell. The cell is then attached to a battery so as to allow a current
of electricity to pass through it, and the minium is thereby reduced to
metallic spongy lead on the negative pole, and oxidized to peroxide of
lead on the positive pole; when the cell is discharged the reduced lead
becomes oxidized, and the peroxide of lead is reduced until the cell
becomes inert.

The improvement consists, as will be seen, in substituting for strips
of lead masses of spongy lead; for, in the Plante cell, the action is
restricted to the surface, while in Faure's modification the action is
almost unlimited. A battery composed of Faure's cells, and weighing 150
lb., is capable of storing up a quantity of electricity equivalent to
one horsepower during one hour, and calculations based on facts in
thermal chemistry show that this weight could be greatly decreased. A
battery of 24 cells, each weighing 14 lb., will keep a strip of platinum
five-eighths of an inch wide, one-thirty-second of an inch thick, and 9
ft. 10 in. long, red-hot for a long time.

The loss resulting from the charging and discharging of this battery is
not great; for example, if a certain quantity of energy is expended in
charging the cells, 80 per cent. of that energy can be reproduced by the