The 19th century French physicist, Ampere, after whom the amp, the standard unit for measuring an electric current, was named; proposed that one could, by means of as many pairs of conducting wires and magnetic needles as there are letters, establish a signaling system. In 1819, it was noticed that an electric current would deflect magnetic needles and that a freely-moving magnetized needle when surrounded by a wire coil will respond to the power of the electrical current in the coil. A device the Galvanometer, to measure currents was built and the would-be electrical telegraphers acquired a signaling instrument using dynamic electricity. This was the final prototype for telegraphy. It was now recognized that there exists a direct relationship between magnetism and electricity and that magnetism can be used to measure a current of electricity and vice versa a current of electricity may be applied to magnetic elements in order to create a signaling device
What had not been figured out early in the 19th century is who needs this instrument? Where was the social necessity to turn these experiments into an invention?
In 1809, Richard Trevithick brought to London the latest wonder of the country's mining areas, an iron wagon-way upon which a steam locomotive ran. At Euston Square in London, he built a round track within a wooden fence and charged one shilling for the ride. In 1825, the first passenger train to go anywhere ran between Stockton and Darlington. The railway age began. Between 1833 and 1843 money was raised to build 2300 miles of railway in the UK. Early railways were only single-track, one track was shared for both ways, which necessitated for the first time instantaneous signaling methods.
One of the many who can lay claim to having invented the telegraph, Edward Davy, saw this clearly. In 1838 he wrote:
The numerous accidents which have occurred on railways seem to call for a remedy of some kind; and when future improvements shall have augmented the speed of railway travelling to a velocity which cannot at present be deemed safe, then every aid which science can afford must be called in to promote this object. Now, there is a contrivance by which, at every station along the railway line, it may be seen, by inspection of a dial, what is the exact situation of the engines running, either towards or from that station and at what speeds they are travelling.
Here then is a real and pressing supervening necessity -- railway safety. And here we are back again to the reality that technology was based on a social need. Also the history of telegraphy offers a clear example of how one technology, in this case the railways, creates a supervening necessity for another, the telegraph.
The word telegraphy comes from Greek. "Tele" means distant and "graphein" to write. So the meaning is writing at a distance The first telegraph wires did indeed run beside railway tracks and were used for operational purposes.
In the year 1836 a young Englishman named William Fothergill Cooke was studying anatomy at University of Heidelberg, Germany. During a physics lecture, he saw a needle telegraph for the first time. Although Cooke had no knowledge in electronics he recognized the chance of this invention for the future. He returned from studying and began constructing and improving an electrical telegraph. Within three weeks he had designed his own.
During this time the English physicist Charles Wheatstone was experimenting with electricity at Kingís College, London. There he made his famous determination of the propagation velocity of electricity. Wheatstone showed that all the effects possible with a short wire could also be produced by a long one, and that the results were to all practical purposes instantaneous. By June 1836, he had demonstrated how this technology could be turned into a telegraph.
In March 1837 Cooke had problems with his telegraph. It seemed that the electrical power could not transmit a signal over long distances. He asked professor Wheatstone for advice. Wheatstone and Cooke formed a partnership of convenience. Cooke was an entrepreneur in search of a fortune, Wheatstone an academic who understood the science of electricity. In June 1837, they were granted a patent on an instrument using six wires, connected to five galvanometer needles arranged in a row across the face of a diamond grid which displayed 20 letters of the alphabet. Each letter was sent in the form of currents flowing down two wires, causing the appropriate needles to swing against stops and point to the right letter. Complex to describe, the system was simple to use: children could, and did, operate it successfully. At 25 July 1837 the first experimental line with the new telegraph was started. The Great Western Railway Company connected the stations Euston Square and Camden Town over a distance of 2.4 kilometres.
Before the telegraph was used in all English railway lines, Cooke and Wheatstone had to improve it. In 1838 they patented their two-needle telegraph. Given that the idea of telegraphy had been widely mooted; that a system using a common scientific device, the galvanometer, had been demonstrated; and that the railways had a need for a signaling system.
In 1840, the first telegram to excite London, that the Queen had given birth was carried from Windsor on the Great Ernest Railways telegraph line, developed by the British inventors Cooke and Wheatstone. Four years later, "What hath God wrought", Morse's first public message a quotation from the Bible, was carried down a telegraph wire running from Washington to Baltimore along the side of rail trakcs. In May 1844, the Democratic National Convention was meeting in Baltimore and Silas Wright, its nominee for vice-president, declined the honor by telegram from Washington. A committee was dispatched by train to check the truth of this communication.