Louis Isidor Duperrey, a French naval officer, born in Paris, Oct. 21, 1786, died Sept.
10, 1865. He entered the navy in 1802, became an ensign in 1811, and was sent in that year to make a hydrographic survey of the coast of Tuscany, which he accomplished in spite of the English cruisers and the hostility of the inhabitants. From 1817 to 1820 he was with Freycinet on his voyage of discovery, in which he had charge of the hydrographic explorations and charts. On his return to France he was promoted to lieutenant, and in 1822 he commanded an expedition for scientific observation in Oceania and on the coast of South America. During a voyage of 32 months he made investigations in hydrography, magnetism, and meteorology, and on the figure of the earth, and collected many thousands of specimens illustrative of zoology and botany. He published a large number of scientific treatises and many maps and charts. His most important researches were in terrestrial magnetism, and he determined accurately the positions of the magnetic poles and the figure of the magnetic equator.