The Express.
London, England, 1847-08-21 00:00:00

THE ELECTRIC TELEGRAPH.

The importance of the electric telegraph as an in-
strument of police, a power in the hands of government, end
a means of social communication, has been already esta-
blished. Next to the application of the principle of steam, It
exhibits the most useful coaversion of an abstract p
to the practical purposes of every-day life. Like all new in-
ventions, the perfecting of the machinery through which It
acts must be a work of time. The electric telegraph was first
put into extensive operation in the United States of America,
and the system adopted was that which is known as the
telegraphic alphabet of Professor Morse. Subsequently,
Messrs. Cooke and Wheatstone took out patents in this
country for someraluable improvements adopted by them:and
it was only last year that Mr. Highton, of Rugby, obtained a
patent for some additional improvements. Much that was
desirable, Newever, remained to be accomplished.
On Saturday last we had an opportunity of witnessing in
operation the improved telegraph of Messrs. Brett and
Little, of Fumival's-inn, through seventeen instruments,
and coils of wire equal to one thousand miles, and
meld not help being struck with the simplicity of the ma-
&fairy, and the certainty and accuracy of the result. The
lest improvement efected by the patentees has reference to
OS apparatus for generating the electrical current, the galvanic
battery. It is well known that the action of the sulphuric
add on the zinc plates of the battery produces incrustation',
sailed sulphate of zinc, which considerably impair its opera-
tion, end require it to be frequently cleated. This evil is
remedied by using three troughs, one placed over the other.
The topmost contains the dilute acid, which drops gently
through small apertures in the bottom into corresponding
apertures in the second trough. In this are contained the
metallic layers of zinc and copper, the interstices between
which are filled by a fine sand. The advantage of the sand
is that it absorbs sufficient moisture from the acid to excite
the required action, and no more ; the superfluous acid being
allowed to percolate through this second trough also by
means of apertures filled with sponge, an the princple of
the common water-filterer, in the last trough which receives
the vitiated liquid. The effect of this arrangement is to
keep the plates clean, and thereby to render the electric ,
current more equable and powerful. It is also well known
that:the system used at present is liable to be affected to such •
degree by the electric condition of the atmosphere as, at
times, to render the telegraph perfectly useless in the hands
of the operator. The indicators, being magnets, tremble as
" things possessed." The bells along the line are set a
ringing, and when the attendants proceed to know what is
the matter, they find it is no artificial communication from
any of the railway kings, but that " Jove's messenger"—
cx(o fulmen demissons —has being playing pranks with
their wires. It is obviously a matter of importance, in such
a case, toknow whose the thunder is, and this the patentees
effect by an ingenious contrivance, which, when the disturb-
ance proceeds from the electric state of the atmosphere,
causes • deer, isolated sound very readily distinguishable
from the ordinary jingle of the bells, by which a person
claims the attention of another at a distance. Where intel-
ligence of an accident is to be transmitted, a strong and
striking sound is given out for the purpose of attracting the
immediate attention of the attendant to the telegraph. The
same battery that is used for ringing the belles also em-
ployed to give action to the telegraph, thus obviating the ex-
pense and inconvenience of requiring a separate battery for