Popular Scientific Recreations: in Natural Philosphy, Astronomy, Geology, Chemistry, etc., etc., etc.Tissandier, Gaston
Science
Popular Scientific Recreations: in Natural Philosphy, Astronomy, Geology, Chemistry, etc., etc., etc.
Tissandier, Gaston
Scientific recreations
As there are a great many other applications of electricity of
which we have to treat,—the Electric Light, and Mr. Edison’s other
inventions,—our space will not permit a much more detailed account of
the telegraph, but there are some incidents connected with its progress
which it would be as well to mention.
[Illustration: Fig. 256.—Electric cable.]
[Illustration: Fig. 257.—Ocean cable.]
Alexander Bain, about 1840, attempted to produce a printing telegraph,
and in 1846 he actually accomplished a registering apparatus, which was
an application of the principles of Dyar and Davy. But although Bain’s
system was good, Morse had the advantage of possession in the United
States, where it was tried, and Bain went out of fashion. Bain’s system
was, in fact, the present chemical “automatic” telegraph, which has
been perfected for rapid transmission.
Bakewell’s instrument, which has been improved upon by later
electricians, is termed the fac-simile telegraph. The message to be
sent is written with a pen which has been dipped in varnish (for ink),
and the characters are inscribed upon prepared tinfoil. The message is
then put upon a cylinder covered with prepared paper, and has a pointer
attached. There is a precisely similar cylinder at the receiving
station. When the cylinders are simultaneously set going, the point at
one will trace a spiral line as the first (transmitting) point passes
round its cylinder. However, as the latter “stylus” meets the varnish
letters a break occurs, and these spaces are exactly reproduced as
blanks at the other end, and the form of the letters can be seen.
Coselli, in his adaptation, caused dark letters to be registered on
a white ground, and thus simplified matters. Since then we have had
printing telegraphs, and dials, and writing machines, one of which will
be described presently.
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