# 1911 Encyclopædia Britannica/Sainte-Claire Deville, Étienne Henri

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​SAINTE-CLAIRE DEVILLE, ÉTIENNE HENRI (1818–1881), French chemist, was born on the 11th of March 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 Besançon, where he acted as dean and professor of chemistry from 1845 to 1851. Returning to Paris in the latter year he succeeded A. J. Balard at the École Normale, and in 1859 became professor at the Sorbonne in place of J. B. A. Dumas, for whom he had begun to lecture in 1853. He died at Boulogne-sur-Seine on the 1st of July 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. But his most important work was in inorganic and thermal chemistry. In 1849 he discovered anhydrous nitric acid (nitrogen pentoxide), a substance interesting as the first obtained of the so-called “anhydrides" of the monobasic acids. In 1855, ignorant of what Wöhler had done ten years previously, he succeeded in obtaining metallic aluminium, and ultimately he devised a method by which the metal 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 for the International Metric Commission then sitting at Paris. With L. J. Troost (b. 1825) he devised a method for determining vapour densities at temperatures up to 1400° C., and, partly with F. Wöhler, he investigated the allotropic orms of silicon and boron. The artificial preparation of minerals, especially of apatite and isomorphous minerals and of crystalline oxides, was another subject in which he made many experiments. But his best known contribution to general chemistry is his work on the phenomena of reversible reactions, which he comprehended under a general theory of “dissociation." He first too up the subject about 1857, and it was in the course of his investigations on it that he devised the apparatus known as the “Deville hot and cold tube.”
His brother, Charles Joseph Sainte-Claire Deville (1814–1876), geologist and meteorologist, was born in St Thomas on the 26th of February 1814. Having attended at the École des Mines in Paris, he assisted Elie de Beaumont in the chair of geology at the Collège de France from 1855 until he succeeded him in 1874. He made researches on volcanic phenomena, especially on the gaseous emanations. He investigated also the variations of temperature in the atmosphere and ocean. He died at Paris on the 10th of October 1876.
His published works include: Études géologiques sur les îles de Ténériffe et de Fago (1848); Voyage géologique aux Antilles et aux îles de Ténériffe et de Fogo (1848–1859); Recherches sur les principaux phénomènes de météorologie et de physique générale aux Antilles (1849); Sur Ies variations périodiques de la température (1866), and Coup d'œil historique sur la géologie (1878).