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

180 HISTORY OF THE ENGLISH TELEGRAPH.
henceforth with great ardor, to the practical realization of the
electric telegraph.
Professor Mlincke's experiment was the only one, at that
time, upon the subject of telegraphing, that Mr. Cooke had seen.
To him the subject was new and surprisingly novel. The experiment which he saw showed that the electric currents, being
conveyed by wires to a distance, could be there caused to
deflect magnetic needles, and thereby to give signals. It did
not provide any means, however, to practically effect telegraphic purposes. It was but a demonstration of science without a
devised appliance in the arts.
MONCKE'S ELECTROMETER EXPERIMENTS.
Fig. 1.
A. - I
The apparatus exhibited by Professor M6ncke, consisted of
two instruments for giving signals by a single needle, placed
in different rooms, with a battery belonging to each, copper
wires being used as the conductor. Fig. 1 represents the apparatus used by Professor Mloncke. Numeral 1 is the near and
2 the distant electrometer; 3 is the battery; 4, the conducting
or circuit wire; 5, the signal; 6, 6, the electrometers, with magnetic needles, and at 7, 7, are steadying pieces, dipping in a
steadying cup of mercury, to support the needle and check
oscillation. The signals given, 5, 5, were a cross and a straight
line, marked on the opposite sides of a disk of card, fixed on a
straw; at the end of which, a magnetic needle was suspended
horizontally in an electrometer coil, by a silk thread. The
effect of this arrangement w-as, that if a current was transmitted from either battery when the opposite ends of the wires
were in connection with the distant telegraphic apparatus,
either the cross would be there exhibited by the motion of the
needle one way, or the line by its motion the other way, according to the direction of the current. The apparatus was worked
by moving the ends of the wires backward and forward between the battery and the coils.