GRATET DE (1750-1801), French geologist and mineralogist, was born at Dolomieu, near Tour-du-Pin, Isere, on June 24, 17 5o. He was admitted in his infancy a member of the Order of Malta. In his nineteenth year he quarrelled with a knight of the galley on which he was serving, and in the duel that ensued killed him. He was condemned to death, but in consideration of his youth was pardoned, after nine months' imprisonment. In 1775 he published his Recherches sur la pesanteur des corps a differ entes distances du centre de la terre, and soon after threw up his commission in the carabineers, and in 1777 accompanied the bailli (afterwards Cardinal L. R. E.) de Rohan to Portugal. In the following years he visited Spain, Sicily, the Pyrenees and Calabria, the scientific results being given in a series of important works. In 1789 and 1790 he studied the Alps, and the mineral dolomite (named after him) was described by Dolomieu in 1791. He re turned to France in that year, bringing with him rich collections of minerals. On Sept. 14, 1792, his friend, the duc de la Roche foucauld was assassinated at Forges, and Dolomieu retired with the widow and daughter of the duke to their estate of Roche Guyon. In 17 98 he accompanied Bonaparte's expedition to Egypt, but ill health compelled his return. On the way home he was captured, and imprisoned at Naples in a pestilential dungeon,. where he remained 21 months. Deprived of writing materials, he made a piece of wood his pen, and with the smoke of his lamp for ink he wrote upon the margins of a Bible, the only book he still possessed, his treatise Sur la philosophie mineralogique et sur l'espece mintirale (1801) . He died at Château-Neuf, Saone-et Loire, on Nov. 26, 1801.
See Lacepede, "loge historique de Dolomieu," in Memoires de la classe des sciences de l'Institut (i8o6) ; Thomson, in Annals of Philo sophy, vol. xii. p. 161 (18o8).