The telegraph manual: a complete history and description of the semaphoric, electric and magnetic telegraphs of Europe, Asia, Africa, and America, ancient and modern.

96 VOLTAIC ELECTRICITY,
it is represented to be, when in good action, nearly equal to
Grove's in power, and superior to it in constancy.
I noticed this battery on the German lines. Telegraphers
expressed themselves highly in favor of it. Its intensity was
highly commensurate with the wants of the telegraph.
Nitric acid, mixed with its own bulk of water, is poured into
the vessel in contact with the carbon. A mixture of sulphuric
acid 1 part, water 25 parts, by measure, is poured into the
porous cup in contact with the zinc. This arrangement may
be varied by using a solid cylinder of carbon in the porous
earthen vessel in the centre, and a zinc cylinder outside next
to the glass. This latter method, I noticed in the central office
in Paris, fiom which place a battery of 40 such couples worked
all the lines from Paris. The batteries are renewed every week.
A current of great intensity is generated by this combination.
In Denmark, Prussia, Austria and other German states, I
noticed the carbon batteries in very extensive use, but no nitric
acid was employed; weak sulphuric acid, 3 of acid to 20 of
water, by measure, is placed in contact with the zinc, which is
well amalgamated, and acid of 1 part sulphuric, to 9 parts water,
is used in contact with the carbon plate. All telegraphers with
whom I discussed the relative merits of the carbon, with that
of the platina, were of the opinion that for telegraphic service
the former was the best, and that without the use of the nitric
acid, a current of sufficient intensity could be generated.
THE GROVE VOLTAIC BATTERY.
The most powerful voltaic battery that has yet been brought
before the public, is that of Professor Grove, invented about
1839. The intensity of its action depends on associating two
metals the most dissimilar in their chemical characters, and
exposing one of them separately to the strongest exciting acid.
This can only be done by using a porous cell, which keeps the
zinc from the distinctive action of the powerful acids employed,
and to which platinum is exposed in a separate compartment.
This battery has been in use on nearly all the telegraph
lines in America until some five years since, when many of
them adopted a modification of the Smee battery, invented by
Mr. C. T. Chester. The following is a description of the Grove
battery as used on the American telegraphs.
Figure 19 represents the zinc cylinder about four inches
high, and three pounds in weight. Fig. 20 is a cylinder with
the platina strip soldered to the arm Bat c. Between A A is D,
an opening, to give free action to the chemicals.
The porous cup, fig. 21, is made of the same materials as
stone-ware, and baked without being glazed. A represents