The cathode must be given a different
form from the anode. If it consists
of a horizontal plate, the metal depos-
ited by the current on the under sur-
face cannot hold. It falls down and
sets the liquid in motion. In order
to prevent this, a metal cone is used
as cathode, which is fixed with its
apex at the centre of a horizontal
circular glass plate. The glass plate is much smaller than the
cross-section of the cylinder, and so chosen that points in its
circumference are approximately equally distant from the base
and from the apex of the cone. By this device all parts of
the surface of the cone are nearly the same distance from the
anode, and the deposited metal distributes itself nearly uni-
formly over the whole. The base of the cone presses closely
against the plate forming the cover. Its height is so chosen
that the glass plate /comes about in the middle of the cylin-
der. The cone and support are made preferably of platinum
or gold. Failing these, silver may be used, which is what I
was obliged to use.
