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

THEE MAGNETO-ELECTRIC TELEGRAPH.
CHAPTER XIX.
Application of Magneto-Electricity to Telegraphing-Its Advantages-Description of Henley's Apparatus-The Brights' Apparatus-Its Comparative
Celerity.
APPLICATION OF MAGNETO-ELECTRICITY TO TELEGRAPHING.
THE magneto-electric telegraph is a needle system. It is
practically employed on the lines of the Magnetic Company
in Great Britain. The Messrs. Bright having tried magnetoelectricity, most faithfully, on the lines of their company for
several years past, commend it as of superior utility. They informed me, that a pair of magnets, costing at Sheffield 30s.,
and perhaps 40s. to 45s. according to finish, will send a strong
current on a well-insulated pole line for 200 miles, and on an
underground wire above 100 miles. Weak signals had been
received on 250 miles underground wires, while on the same
lines, a battery of six twelve-cells, was necessary to perform
the work, at a cost of ~7, 10s., besides the cost of renewals.
A magnet, if the keepers are put on when the instrument is
not in use, will retain its magnetism for an indefinite time.
They had worked magnets two and three years without remagnetizing them. The experiments made with magneto-electricity by these gentlemen, establish the practicability of its
application to telegraphing; in this, however, there is a difference of opinion among scientific telegraphers. Mr. Bakewell,
in his late work on electricity, asserts, that electricity generated
in this manner is small in quantity, and of comparatively great
intensity, therefore more liable to be diverted from this circuit
by imperfect insulation; and as another objection to this form
of telegraph, he states, that the needle sends signals in one
direction only. Two communicating wires are consequently
required to obtain the same combination of deflections that
can be given with a single wire, when a voltaic current is
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