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

ALEXANDERrS ELECTRIC TELEGRAPH. 141
painted on them in the usual order. The wires serve merely
for communication, and we shall now describe the apparatus
by which they work.
This consists, at the south end, of a pair of plates, zinc and
copper, forming a galvanic trough, placed under the keys; and
at the north end, of thirty steel magnets, about four inches
long, placed close behind the letters painted on the screen. The
magnets move horizontally on axes, and are poised within
a flat ring of copper wire, formed of the ends of the communicating wires. On their north ends they carry small square
bits of black paper, which project in front of the screen, and
serve as opercula, or covers, to conceal the letters. When any
wire is put in communication with the trough at the south
end, the galvanic influence is instantly transmitted to the north
end; and in accordance with the well-known law, discovered
by CErsted, the magnet at the end of that wire instantly turns
round to the right or left, bearing with it the operculum ot
black paper, and unveiling a letter. When the key, A, for instance, is pressed down with the finger at the south end, the
wire attached to it is immediately put in communication with
the trough; and at the same instant, letter A, at the north end
is unveiled, by the magnet turning to the right, and withdrawing the operculum. When the finger is removed from the
key, it springs back to its place; the communication with the
trough ceases;. the magnet resumes its position, and the letter
is again covered. Thus by pressing down with the finger, in
succession, the keys corresponding to any word or name, we
have the letters forming that word, or name, exhibited at the
other end; the name VICTORIA, for instance, which was the
maiden effort of the telegraph, on the exhibition before the
Society of Arts, above referred to.
The above description is all that I have been able to obtain
in relation to this plan of an electric telegraph; and here introduce, fig. 3, to illustrate it. The thirty needles are represented
on the screen, each carrying a shade, which conceals the letter
when the needle is vertical. The needle belonging to the letter
F, is, however, deflected, and the letter is exposed. The screen
is supposed to be at the receiving station. To the left hand of
the screen, thirty wires, e e, are seen joined to one, a; the
other thirty wires, d d, are seen below the screen.