SAINTE-CLAIRE DEVILLE, ETIENNE HENRI (1818-1881), French chemist, was born on March II, 1818, in the island of St. Thomas, West Indies, where his father was French consul. Together with his elder brother Charles he was educated in Paris at the College Rollin. In 1844, having graduated as doctor of medicine and doctor of science, he was appointed to organize the new faculty of science at Besancon, where he acted as dean and professor of chemistry from 1845 to 1851. He succeeded A. J. Balard at the Ecole Normale, Paris, in 1851, and in 1859 became professor at the Sorbonne in place of J. B. A. Dumas (q.v.). He died at Boulogne-sur-Seine on July 1, 1881. He began his experimental work in 1841 with investigations of oil of turpentine and tolu balsam, in the course of which he discovered toluene (q.v.). His most important work was in inorganic and thermal chemistry. In 1849 he discovered nitrogen pentoxide, the first of the so-called "anhydrides" of the mono basic acids to be isolated. In 1855 he devised a method by which
aluminium (q.v.) could be prepared on a large scale by the aid of sodium, the manufacture of which he also developed. With H. J. Debray (1827-1888) he worked at the platinum metals, his object being on the one hand to prepare them pure, and on the other to find a suitable metal for the standard metre. With L. J. Troost he devised a method for determining vapour densities at temperatures up to C, and, partly with F. Wohler, he investigated the halides of silicon and boron. His best known contribution to chemistry is his work on the phenomena of reversible reactions (see CHEMICAL ACTION), which he included under the term of "dissociation." He first took up the subject about 1857, and it was during his important investigations in this field that he devised the apparatus known as the "Deville hot and-cold tube."