Overview
The
Electric Telegraph was an early system of sending messages over long distances by wire. However, unlike a telephone
which reproduces a voice message the telegraph used the Morse Code of alternating short and long signals called dots and dashes.
Each letter had its own dot-dash combination and the code could be deciphered at the receiving end so the message could be
read.
The first commercial
electrical telegraph was co-developed by Sir William Fothergill
Cooke and Charles Wheatstone, and entered use on the Great Western Railway in Britain. It ran for 13 miles (21 km) from
Paddington station to West Drayton and came into operation on July 9 1839 It was patented in the
United Kingdom in 1837, and was first successfully demonstrated by Cooke and Wheatstone on July 25 1837
between Euston and Camden Town in London.
In 1843 Scottish inventor Alexander Bain invented
a device that could be considered the first facsimile machine. He called his invention a "recording telegraph". Bain's telegraph
was able to transmit images by electrical wires.
In
1855 an Italian abbot, Giovanni Caselli, also created an electric telegraph that could transmit
images. Caselli called his invention "Pantelegraph". Pantelegraph was successfully tested and approved for a telegraph line
between Paris and Lyon.
The first commercially
successful transatlantic telegraph cable was successfully completed on July 18 1866. The lasting
connections were achieved by the ship SS Great Eastern, captained by Sir James Anderson. Earlier transatlantic submarine
cables installations were attempted in 1857, 1858 and 1865.
The 1857 cable only operated intermittently for a few
days or weeks before it failed.
The study of underwater telegraph cables accelerated interest in mathematical analysis
of very long transmission lines. The telegraph lines from Britain to India were connected in 1870 (those several companies
combined to form the Eastern Telegraph Company in 1872).
Further advancements
in telegraph technology occurred in the early 1870s, when Thomas Edison devised a full duplex two-way telegraph and then doubled
its capacity with the invention of quadruplex telegraphy in 1874. Edison filed for a U.S. patent on the duplex telegraph on
September1 1874 and received U.S. Patent 480,567 on August 9 1892.
The telegraph across
the Pacific was completed in 1902, finally encircling the world.
