means of heavy rubber bands stretched around the carbon. The rod,
forming the terminal of the zinc, passes through a porcelain bushing
on the cover plate to obviate short circuits. This type of cell has an
electromotive force of about 1.55 volts and recuperates very quickly
after severe use. It also has considerably lower internal resistance
than the type of LeClanché cell employing a porous cup, and,
therefore, is capable of generating a considerably larger current.

Cells of this general type have assumed a variety of forms. In some
the carbon electrode, together with the broken carbon and peroxide of
manganese, were packed into a canvas bag which was suspended in the
electrolyte and usually surrounded by the zinc electrode. In other
forms the carbon electrode has moulded with it the manganese
depolarizer.

In order to prevent the salts within the cell from creeping over the
edge of the containing glass jar and also over the upper portion of
the carbon electrode, it is common practice to immerse the upper end
of the carbon element and also the upper edge of the glass jar in hot
paraffin.

In setting up the LeClanché cell, place not more than four ounces of
white sal ammoniac in the jar, fill the jar one-third full of water,
and stir until the sal ammoniac is all dissolved. Then put the carbon
and zinc elements in place. A little water poured in the vent hole of
the porous jar or carbon cylinder will tend to hasten the action.

An excess of sal ammoniac should not be used, as a saturated solution
tends to deposit crystals on the zinc; on the other hand, the solution
should not be allowed to become too weak, as in that case the chloride