Electrical telegraph
In the 19th century, Yoruba drummers used talking drums to mimic human tonal language[7][8] to communicate complex messages – usually regarding news of birth, ceremonies, and military conflict – over 4–5 mile distances.
[15] Telegraphs employing electrostatic attraction were the basis of early experiments in electrical telegraphy in Europe, but were abandoned as being impractical and were never developed into a useful communication system.
Another very early experiment in electrical telegraphy was an "electrochemical telegraph" created by the German physician, anatomist and inventor Samuel Thomas von Sömmering in 1809, based on an earlier 1804 design by Spanish polymath and scientist Francisco Salva Campillo.
Thus, messages could be conveyed electrically up to a few kilometers (in von Sömmering's design), with each of the telegraph receiver's wires immersed in a separate glass tube of acid.
In 1830 William Ritchie improved on Ampère's design by placing the magnetic needles inside a coil of wire connected to each pair of conductors.
[20] In 1825, William Sturgeon invented the electromagnet, with a single winding of uninsulated wire on a piece of varnished iron, which increased the magnetic force produced by electric current.
[21] During his tenure at The Albany Academy from 1826 to 1832, Henry first demonstrated the theory of the 'magnetic telegraph' by ringing a bell through one-mile (1.6 km) of wire strung around the room in 1831.
[34] His work was taken over and developed by Moritz von Jacobi who invented telegraph equipment that was used by Tsar Alexander III to connect the Imperial palace at Tsarskoye Selo and Kronstadt Naval Base.
The page of Gauss's laboratory notebook containing both his code and the first message transmitted, as well as a replica of the telegraph made in the 1850s under the instructions of Weber are kept in the faculty of physics at the University of Göttingen, in Germany.
By 1837, William Fothergill Cooke and Charles Wheatstone had co-developed a telegraph system which used a number of needles on a board that could be moved to point to letters of the alphabet.
A demonstration four-needle system was installed on the Euston to Camden Town section of Robert Stephenson's London and Birmingham Railway in 1837 for signalling rope-hauling of locomotives.
[40] Cooke and Wheatstone had their first commercial success with a system installed on the Great Western Railway over the 13 miles (21 km) from Paddington station to West Drayton in 1838.
The insulation failed on the underground cables between Paddington and West Drayton,[42][43] and when the line was extended to Slough in 1843, the system was converted to a one-needle, two-wire configuration with uninsulated wires on poles.
Originally, the armature was intended to make marks on paper tape, but operators learned to interpret the clicks and it was more efficient to write down the message directly.
[63] For a brief period, starting with the New York–Boston line in 1848, some telegraph networks began to employ sound operators, who were trained to understand Morse code aurally.
[64] Royal Earl House developed and patented a letter-printing telegraph system in 1846 which employed an alphabetic keyboard for the transmitter and automatically printed the letters on paper at the receiver,[65] and followed this up with a steam-powered version in 1852.
[67] David Edward Hughes invented the printing telegraph in 1855; it used a keyboard of 26 keys for the alphabet and a spinning type wheel that determined the letter being transmitted by the length of time that had elapsed since the previous transmission.
In the latter half of the 1800s, several inventors worked towards creating a method for doing just that, including Charles Bourseul, Thomas Edison, Elisha Gray, and Alexander Graham Bell.
Michael Faraday and Wheatstone soon discovered the merits of gutta-percha as an insulator, and in 1845, the latter suggested that it should be employed to cover the wire which was proposed to be laid from Dover to Calais.
[74] In 1849, C. V. Walker, electrician to the South Eastern Railway, submerged a 2 miles (3.2 km) wire coated with gutta-percha off the coast from Folkestone, which was tested successfully.
[73] John Watkins Brett, an engineer from Bristol, sought and obtained permission from Louis-Philippe in 1847 to establish telegraphic communication between France and England.
It was successfully completed on 18 July 1866 by the ship SS Great Eastern, captained by Sir James Anderson, after many mishaps along the way.
[75] John Pender, one of the men on the Great Eastern, later founded several telecommunications companies primarily laying cables between Britain and Southeast Asia.
Before telegraphy, absolute time could be obtained from astronomical events, such as eclipses, occultations or lunar distances, or by transporting an accurate clock (a chronometer) from one location to the other.
After the French extended their telegraph lines to the coast of the Black Sea in late 1854, war news began reaching London in two days.
These prompt daily news reports energised British public opinion on the war, which brought down the government and led to Lord Palmerston becoming prime minister.
[99] During the American Civil War the telegraph proved its value as a tactical, operational, and strategic communication medium and an important contributor to Union victory.
Soon after the shelling of Fort Sumter, the South cut telegraph lines running into D.C., which put the city in a state of panic because they feared an immediate Southern invasion.
[103] The British government censored telegraph cable companies in an effort to root out espionage and restrict financial transactions with Central Powers nations.
Resistance movements in occupied Europe sabotaged communications facilities such as telegraph lines,[107] forcing the Germans to use wireless telegraphy, which could then be intercepted by Britain.
