Destutt de Tracy (Antoine Louis de Claude) Count, French materialist philosopher, b. 20 July, 1754. His family was of Scotch origin. At first a soldier, he was one of the first noblemen at the Revolution to despoil himself of his title. A friend of Lafayette, Condorcet, and Cabanis, he was a complete sceptic in religion; made an analysis of Dupuis' Origine de tous les Cultes (1804), edited Montesquieu and Cabanis, was made a member of the French Academy (1808), and wrote several philosophical works, of which the principal is Elements of Ideology. He was a great admirer of Hobbes. Died Paris, 9 March, 1836. Des Vignes (Pietro), secretary to Frederick II. (1245-49). Mazzuchelli attributes to him the treatise De Tribus Impostoribus. Detrosier (Rowland), social reformer and lecturer, b. 1796, the illegitimate son of a Manchester man named Morris and a Frenchwoman. In his early years he was "for whole days without food." Self-educated, he established the first Mechanics' Institute in England at Hulme, gave Sunday scientific lectures, and published several discourses in favor of secular education. He became secretary of the National Political Union. He was a Deist. Like Bentham, who became his friend, he bequeathed his body for scientific purposes. Died in London, 23 Nov. 1834. Deubler (Konrad). The son of poor parents, b. Goisern, near Ischl, Upper Austria, 26 Nov. 1814. Self-taught amid difficulties, he became the friend of Feuerbach and Strauss, and was known as "the Peasant Philosopher." In 1854 he was indicted for blasphemy, and was sentenced to two years' hard labor and imprisonment during pleasure. He was incarcerated from 7 Dec. '54, till Nov. '56 at Brünn, and afterwards at Olmutz, where he was released 24 March, 1857. He returned to his native place, and was visited by Feuerbach. In '70 he was made Burgomaster by his fellow-townsmen. Died 30 March, 1884. Deurhoff (Willem), Dutch writer, b. Amsterdam, March 1650. Educated for the Church, he gave himself to philosophy, translated the works of Descartes, and was accused of being a follower of Spinoza. Forced to leave his country, he took refuge in Brabant, but returned to Holland, where he died 10 Oct. 1717. He left some followers. De Wette. (See Wette M. L. de). D'Holbach. See Holbach (P. H. D. von), Baron.