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

SALVA'S AND SCHILLING' ELECTRIC TELEGRAPHS. 135.
constituting the letter, and the whole letter is rendered visible
at once." This table is placed at any one station, and the
electrical machine at the other, with seventy-two wires enclosed
in a glass tube connecting the two stations. He could have
operated with equal efficiency by using thirty-seven wires,
having one wire for a common communicating wire, or with
thirty-six wires, by substituting the ground for his common
wire. It does not appear that it was ever operated to any considerable extent.
DR. SALVA'S ELECTRIC SPARK TELEGRAPH.
In 1798, Dr. Salva, in Madrid, constructed a similar telegraph as that suggested by Reizen, as will be found on reference to Vorgt's lMagazine, vol..xi., p. 4. The " Prince of Peace"
witnessed his experiments with much satisfaction, and the Infant Don Antonio engaged with Dr. Salva in improving his instrument. It is stated that his experiments extended through
many miles of wire. No description of his plans were given to
the public.
BARON SCHILLING'S ELECTRIC TELEGRAPH.
The following, in relation to Schilling's telegraph, is taken
from the Polytechnic Central Journal, Nos. 31, 32, 1838:
" Baron Schilling, of Cronstadt, a Russian counsellor of state,
likewise occupied himself with telegraphs by electricity (see
Allgem Bauztg, 1837, No. 52, p. 440), and had the merit of
having presented a much simpler contrivance, and of removing
some of the difficulties of the earlier plans. He reckoned many
variations to the right or left, following in a certain order for a
telegraphic sign, as, indeed, in this manner, the needle
was strongly varied, and only came to rest gradually after
many repeated vibrations; he introduced a small rod of platinum, with a scoop, which dipped into a vessel of quicksilver,
placed beneath the needle, and, by the check given, changed
the xvibration of the needle into sudden jerks. In order to apprise the attendant of a telegraphic dispatch, he loosed an
alarm. How much of this contrivance was Schilling's own,
or whether a portion of it was not an imitation of Gauss and
Weber, the author cannot decide; but that Schilling had already
experimented, probably with a more imperfect apparatus, before the Emperor Alexander, and still later before the Emperor
Nicholas, is affirmed by the documents quoted."