designed for regulating the flow of the liquid into the pile. When the
cock, r, is too widely open, the liquid might have a tendency to
flow over the edges of the vessel; but this would close the orifice of
the tube, A, and, as the air would then no longer enter the reservoir,
R, the flow would be stopped automatically. The second tube of the
first vessel is connected with a lead tube, 1, one of the extremities
of which enters the second vessel. The other tubes are arranged in the
same way in the other vessels. The renewal of the liquids is effected
by displacement, in flowing upward from one element over into another;
and the liquids make their exit from the pile at D, after having
served six times. The electrodes of the two first elements are
represented as renewed in the cut, in order to show the arrangement of
the tubes.

[Illustration: ESTEVE'S AUTOMATIC PILE.]

_Dimensions._--The zinc, 2, has a superficies of 15×20 centimeters,
and is cut out of the ordinary commercial sheet metal. It may be
turned upside down when one end has become worn away, thus permitting
of its being entirely utilized. The negative electrode is formed of
four carbons, which have, each of them, a superficies of 8×21
centimeters. These four carbons are less fragile and are more easily
handled than two having the same surface. Their arrangement is shown
at the left of the figure. They are fixed to a strip of copper, a,
to which is soldered another strip, L, bent at right angles. There are
thus two pairs of carbon per element, and these are simply suspended
from a piece of wood, as shown in the figure. Upon this wooden holder
will be seen the two strips, LL, that are designed to be put in
contact with the zinc of the succeeding element by means of pinchers
that connect the electrodes with one another. This arrangement permits