.

It was necessary to obtain a battery with a constant current. It is
known that the elements of modern batteries are generally composed of
retort coal, zinc, and copper. Copper was absolutely wanting to the
engineer, who, notwithstanding all his researches, had never been able
to find any trace of it in Lincoln Island, and was therefore obliged
to do without it. Retort coal, that is to say, the hard graphyte which
is found in the retorts of gas manufactories, after the coal has been
dehydrogenised, could have been obtained, but it would have been
necessary to establish a special apparatus, involving great labour. As
to zinc, it may be remembered that the case found at Flotsam Point was
lined with this metal, which could not be better utilised than for
this purpose.

Cyrus Harding, after mature consideration, decided to manufacture a
very simple battery, resembling as nearly as possible that invented by
Becquerel in 1820, and in which zinc only is employed. The other
substances, azotic acid and potash, were all at his disposal.

The way in which the battery was composed was as follows, and the
results were to be attained by the reaction of acid and potash on each
other. A number of glass bottles were made and filled with azotic
acid. The engineer corked them by means of a stopper through which
passed a glass tube, bored at its lower extremity, and intended to be
plunged into the acid by means of a clay stopper secured by a rag.
Into this tube, through its upper extremity, he poured a solution of
potash, previously obtained by burning and reducing to ashes various
plants, and in this way the acid and potash could act on each other
through the clay.

Cyrus Harding then took two slips of zinc, one of which was plunged
into azotic acid, the other into a solution of potash. A current was
immediately produced, which was transmitted from the slip of zinc in
the bottle to that in the tube, and the two slips having been
connected by a metallic wire the slip in the tube became the positive
pole, and that in the bottle the negative pole of the apparatus. Each
bottle, therefore, produced as many currents as united would be
sufficient to produce all the phenomena of the electric telegraph.
Such was the ingenious and very simple apparatus constructed by Cyrus
Harding, an apparatus which would allow them to establish a
telegraphic communication between Granite House and the corral.

On the 6th of February was commenced the plan