Chappe, Claude

SUBJECT AREA: Telecommunications

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b. 25 December 1763 Brulon, France

d. 23 January 1805 Paris, France

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French engineer who invented the semaphore visual telegraph.

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Chappe began his studies at the Collège de Joyeuse, Rouen, and completed them at La Flèche. He was educated for the church with the intention of becoming an Abbé Commendataire, but this title did not in fact require him to perform any religious duties. He became interested in natural science and amongst other activities he carried out experiments with electrically charged soap bubbles.

When the bénéfice was suppressed in 1781 he returned home and began to devise a system of telegraphic communication. With the help of his three brothers, particularly Abraham, and using an old idea, in 1790 he made a visual telegraph with suspended pendulums to relay coded messages over a distance of half a kilometre. Despite public suspicion and opposition, he presented the idea to the Assemblée Nationale on 22 May 1792. No doubt due to the influence of his brother, Ignace, a member of the Assemblée Nationale, the idea was favourably received, and on 1 April 1793 it was referred to the National Convention as being of military importance. As a result, Chappe was given the title of Telegraphy Engineer and commissioned to construct a semaphore (Gk. bearing a sign) link between Paris and Lille, a distance of some 240 km (150 miles), using twenty-two towers. Each station contained two telescopes for observing the adjacent towers, and each semaphore consisted of a central beam supporting two arms, whose positions gave nearly two hundred possible arrangements. Hence, by using a code book as a form of lookup table, Chappe was able to devise a code of over 8,000 words. The success of the system for communication during subsequent military conflicts resulted in him being commissioned to extend it with further links, a work that was continued by his brothers after his suicide during a period of illness and depression. Providing as it did an effective message speed of several thousand kilometres per hour, the system remained in use until the mid-nineteenth century, by which time the electric telegraph had become well established.

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Further Reading

R.Appleyard, 1930, Pioneers of Electrical Communication.

International Telecommunications Union, 1965, From Semaphore to Satellite, Geneva.

See also: Morse, Samuel Finley Breeze

KF