Geoscience Reference
In-Depth Information
11
Thermodynamics and the
cooling Earth revisited
In the middle of the nineteenth century numerous oceanographic
voyages traversed the world's oceans revealing details of submarine
topography and hitherto unseen animals. At much the same time tele-
graphic communications were being developed and the network in
Britain expanded rapidly in the 1830s as the railways were laid out. By
1850 Britain had telegraphic links with France and Ireland, but it was
soon realised that theoretically it could be possible to link Europe with
distant continents including North America and Africa. In 1858 the first
transatlantic cable was laid between Europe and North America but
a month later problems with the insulation led to signal failure. In 1865
a new attempt to lay a cable followed but the line was lost. Undaunted,
the steamer the Great Eastern set out on 13 July 1866 and began to lay a
working cable for 2,000 miles between Valentia Island off southwest
Ireland to Heart's Content, Newfoundland. Unusual for the time, this
ship was powered by both paddles and screw propellers. It completed its
voyage and the link by 27 July and a message was sent from Canada to
Edward, Lord Stanley, the Prime Minister. The following day Queen
Victoria sent amessage in the opposite direction to Andrew Johnson, the
President of the United States, from Osborne House and expressed her
hope that the cable might 'serve as an additional bond of union between
the United States and England'. Much of the credit for the success of
telegraphy is owed to a Belfast man, William Thomson (1824-1907)
(Figure
11.1
) who was a director of the Atlantic Telegraph Company,
and rewarded for this work with a knighthood in 1874. Thomson carried
out a great deal of research on cables, determining the diameter required
and the purity of copper necessary to ensure that they did not malfunc-
tion, and he also invented a submarine telegraph receiver which allowed
the incoming message, in Morse Code, to be recorded.
