The Consolidated Electric Light Company has now completed the secondary
battery which has for some time engaged the attention of its officers,
and their regular manufacture and use for electric lighting stations
have been fairly entered upon. Among other places to which the batteries
have been sent and put into work is Colchester, where the company
has for some time had an installation at work, chiefly employing
incandescent lamps. The battery consists of lead electrodes, anode and
cathode being of the same character. They are constructed of narrow
ribbons of lead, each element being made from long lengths of the ribbon
about or nearly 0.20 in. width, rolled together into a flat cake like
rolls of narrow webbing, as illustrated by the annexed diagram, Fig.
1, the greater part of the ribbon being very thin and flat; but
intermediate thicker ribbons are also employed, as in Fig. 2, this
thicker ribbon being corrugated as shown, and affording passage room
for the circulation of the electrolyte. From four to eight coils of the
plain ribbons are between every pair of corrugated ribbons. They are
wound up together tightly, and pressed into the nearly rectangular form
shown. The bar for suspending the coil plates so made in the cells is
soldered to the coil. The object of this construction is of course to
obtain large lead surface, and of course a much larger surface is so
obtained than could be practically obtained from plain lead plates in
the same compass. A battery thus made may be seen at the offices of the
company, 110 Cannon Street.
[Illustration: FIG. 1. FIG. 2.]
A very ingenious device for cutting the battery out of circuit when
charged as much as is thought desirable is used by the company. In a
cell is an element which has a determined lower capacity than those in
the rest of the battery. Over this element is placed a gas-tight chamber
in which is a diaphgram, this diaphragm being of very flexible material
placed in the cover of the box of cells. When charging has proceeded as
long as is desirable, or proceeds too fast, hydrogen is evolved, and
this collecting in the chamber referred to acts upon the diaphragm, and
by means of a rod connected thereto, switches the current, which is
supplied to an electro-magnet and by which circuit is made through the
medium of mercury contacts. The object, of this is to save the
battery from destruction by over-charging or charging by too large a
current.--_The Engineer_.
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