Scientific American Supplement, No. 384, May 12, 1883Various
Science
Scientific American Supplement, No. 384, May 12, 1883
Various
Science -- Periodicals
Nothing, however, in this document authorizes the belief that Charles
Marshall ever realized his idea, so we must proceed to 1774 to find
Lesage, of Geneva, constructing a telegraph that was based upon the
principle indicated twenty years before in the letter of Renfrew.
The apparatus that Lesage devised (Fig. 1) was composed of 24 wires
insulated from one another by a non conducting material. Each of these
wires corresponded to a small pith ball suspended by a thread. On
putting an electric machine in communication with such or such a one of
these wires, the ball of the corresponding electrometer was repelled,
and the motion signaled the letter that it was desired to transmit. Not
content with having realized an electric telegraph upon a small scale,
Lesage thought of applying it to longer distances.
"Let us conceive," said he in a letter written June 22, 1782, to Mr.
Prevost, of Geneva, "a subterranean pipe of enameled clay, whose cavity
at about every six feet is separated by partitions of the same material,
or of glass, containing twenty-four apertures in order to give passage
to as many brass wires as these diaphragms are to sustain and keep
separated. At each extremity of this pipe are twenty-four wires that
deviate from one another horizontally, and that are arranged like the
keys of a clavichord; and, above this row of wire ends, are distinctly
traced the twenty-four letters of the alphabet, while beneath there is a
table covered with twenty-four small pieces of gold-leaf or other easily
attractable and quite visible bodies."
Lesage had thought of offering his secret to Frederick the Great; but
he did not do so, however, and his telegraph remained in the state of a
curious cabinet experiment. He had, nevertheless, opened the way, and,
dating from that epoch, we meet with a certain number of attempts at
electrostatic telegraphy. [1]
[Footnote 1: Advantage has been taken of a letter from Alexander Volta
to Prof. Barletti (dated 1777), indicating the possibility of firing his
electric pistol from a great distance, to attribute to him a part in the
invention of the telegraph. We have not shared in this opinion, which
appears to us erroneous, since Volta, while indicating the possibility
above stated, does not speak of applying such a fact to telegraphy.]
The first in date is that of Lemond, which is spoken of by Arthur Young
(October 16, 1787), in his _Voyage Agronomique en France_:
Public-domain text, read in full here on John Shaqi.
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