Sir Charles Wheatstone FRS

SUBJECT AREA: Telecommunications

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Wheatstone's family moved to London when he was 4 years old. He was educated at various schools in London and excelled in physics and mathematics. He qualified for a French prize but forfeited it because he was too shy to recite a speech in French at the prize-giving.

An uncle, also called Charles Wheatstone, has a musical instrument manufacturing business where young Charles went to work. He was fascinated by the science of music, but did not enjoy business life. After the uncle's death, Charles and his brother William took over the business. Charles developed and patented the concertina, which the firm assembled from parts made by "outworkers". He devoted much of his time to studying the physics of sound and mechanism of sound transmission through solids. He sent speech and music over considerable distances through solid rods and stretched wires, and envisaged communication at a distance. He concluded, however, that electrical methods were more promising.

In 1834 Wheatstone was appointed Professor of Experimental Philosophy—a part-time posi-tion—in the new King's College, London, which gave him some research facilities. He conducted experiments with a telegraph system using several miles of wire in the college corridors. Jointly with William Fothergill Cooke, in 1837 he obtained the first patent for a practical electric telegraph, and much of the remainder of his life was devoted to its improvement. In 1843 he gave a paper to the Royal Society surveying the state of electrical measurements and drew attention to a bridge circuit known ever since as the "Wheatstone bridge", although he clearly attributed it to S.H.Christie. Wheatstone devised the "ABC" telegraph, for use on private lines by anyone who could read, and a high-speed automatic telegraph which was adopted by the Post Office and used for many years. He also worked on the French and Belgian telegraph systems; he died when taken ill on a business visit to Paris.

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SUBJECT AREA: Broadcasting, Telecommunications

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Brought up in poor, almost Dickensian, circumstances, at the age of 13 years Heaviside, a nephew by marriage of Sir Charles Wheatstone, went to Camden House Grammar School. There he won a medal for science, but he was forced to leave because his parents could not afford the fees. After a year of private study, he began his working life in Newcastle in 1870 as a telegraph operator for an Anglo-Dutch cable company, but he had to give up after only four years because of increasing deafness. He therefore proceeded to spend his time studying theoretical aspects of electrical transmission and communication, and moved to Devon with his parents in 1889. Because the operation of many electrical circuits involves transient phenomena, he found it necessary to develop what he called operational calculus (which was essentially a form of the Laplace transform calculus) in order to determine the response to sudden voltage and current changes. In 1893 he suggested that the distortion that occurred on long-distance telephone lines could be reduced by adding loading coils at regular intervals, thus creating a matched-transmission line. Between 1893 and 1912 he produced a series of writings on electromagnetic theory, in one of which, anticipating a conclusion of Einstein's special theory of relativity, he put forward the idea that the mass of an electric charge increases with its velocity. When it was found that despite the curvature of the earth it was possible to communicate over very great distances using radio signals in the so-called "short" wavebands, Heaviside suggested the presence of a conducting layer in the ionosphere that reflected the waves back to earth. Since a similar suggestion had been made almost at the same time by Arthur Kennelly of Harvard, this layer became known as the Kennelly-Heaviside layer.

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See also: Appleton, Sir Edward Victor