In 1837, Professor Stratingh, of Groninque, Holland, devised a telegraph
in which the signals were made by electro-magnets actuating the hammers
of two gongs or bells of different tone; and M. Amyot invented an
automatic sending key in the nature of a musical box. From 1837-8,
Edward Davy, a Devonshire surgeon, exhibited a needle telegraph in
London, and proposed one based on the discovery of Arago, that a piece
of soft iron is temporarily magnetised by the passage of an electric
current through a coil surrounding it. This principle was further
applied by Morse in his electro-magnetic printing telegraph. Davy was a
prolific inventor, and also sketched out a telegraph in which the gases
evolved from water which was decomposed by the current actuated a
recording pen. But his most valuable discovery was the 'relay,' that is
to say, an auxiliary device by which a current too feeble to indicate
the signals could call into play a local battery strong enough to make
them. Davy was in a fair way of becoming one of the fathers of the
working telegraph, when his private affairs obliged him to emigrate to
Australia, and leave the course open to Cooke and Wheatstone.
CHAPTER II.
CHARLES WHEATSTONE.
The electric telegraph, like the steam-engine and the railway, was a
gradual development due to the experiments and devices of a long train
of thinkers.
Pages:
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33