CHAPPE, CLAUDE (1763–1805), French engineer, was born at Brûlon (Sarthe) in 1763. He was the inventor of an optical telegraph which was widely used in France until it was superseded by the electric telegraph. His device consisted of an upright post, on the top of which was fastened a transverse bar, while at the ends of the latter two smaller arms moved on pivots. The position of these bars represented words or letters; and by means of machines placed at intervals such that each was distinctly visible from the next, messages could be conveyed through 50 leagues in a quarter of an hour. The machine was adopted by the Legislative Assembly in 1792, and in the following year Chappe was appointed ingénieur-télégraphe; but the originality of his invention was so much questioned that he was seized with melancholia and (it is said) committed suicide at Paris in 1805.
His elder brother, Ignace Urbain Jean Chappe (1760–1829), took part in the invention of the telegraph, and with a younger brother, Pierre François, from 1805 to 1823 was administrator of the telegraphs, a post which was also held by two other brothers, René and Abraham, from 1823 to 1830. Ignace was the author of a Histoire de la télégraphie (1824). An uncle, Jean Chappe d’Auteroche (1728–1769), was an astronomer who observed two transits of Venus, one in Siberia in 1761, and the other in 1769 in California, where he died.