DUPERREY, Louis Isidore (1786-1865), a French navigator and scientific investigator, was born at Paris, entered the navy in 1803, took part in the military operations of 1809 at Brest and Rochefort, and assisted in the hydrographical survey of the coast of Tuscany carried on during that and the following year. From 1817 to 1820 he served under Freycinet in his great voyage round the world, being intrusted with the hydrographic operations on board the “Urania;” and he contributed largely to the preservation of the crew and the scientific collections when his vessel was wrecked at the Malouin Islands. In 1822 he attained the rank of lieutenant, and was intrusted with the command of the “Coquille,” which during the next three years was engaged in scientific explorations in the South Pacific and along the coasts of South America. From this voyage he brought back not only great additions to cartography and important data in regard to the currents of the Pacific, but also numerous pendulum observations, serving to determine the magnetic equator, and to prove the equality of the flattening of the two hemispheres. During the reet of his life he devoted himself mainly to the investigation of terrestrial magnetism; and the value of his labours was recognized by his admission into the Académie des Sciences in 1842. He died in August 1865.

The following are his principal works :—The Partie historique, the Hydrographie, and the Physique of the Voyage autour du Monde sur la Coquille, Paris 1826-1830; and extensive contributions to Becquerel’s Traite de Γ Electricité.