DIDEROT, DENIS, a celebrated French encyclopedist and philosophical writer, was born at Langres, in Champagne, 5th Oct., 1713. He was educated for the church at the college of his native town, and subsequently at that of D'Harcourt, Paris; but dis liking the clerical office, and after having made a trial of law, a profession which he also found uncongenial, he finally resolved, after various vicissitudes, upon becoming a litterateur. For some years, however, his mode of life was very precarious. On one occa sion, being reduced to the greatest extremities, he seriously resolved that if the world should ever prosper with him, he, not ignorant of misfortune, would never disregard the applications of the indigent. This resolution was religiously kept ; for after having attqined at position of comparative affluence, he was continually surrounded by applicants desirous of obtaining assistance, which, whether in the shape of money or instruction, D. was always willing to afford them. Although very poor, D. married in 1743. Necessity now drove him to increased exertions. He translated the History of Greece from the English of Stanyan, receiving for this work the sum of 100 crowns. Soon afterwards followed the Essai sur le iThrite et laVertu; the Pensees Philisophiques, written, it is said, in the space of four days; and the Interpr8ation de la _Nature. Shortly after appeared his Lettre sur les Aveugles, for the writing of which he was confined three months in the prison of Vincennes. Believing that it was, among other things, his vocation to regen erate the theater, he produced a melodrama (1758), entitled ..Le 7'ere de Famille. It was unsuccessful, and was followed by others equally so, so that it was said, "Le Pere de Famille a etc le pare d'une famine deplorable." But D.'s great work was the Encyclopcedie, of which he and D'Alembert were the joint editors. It was commenced in 1749. D., .besides revising all the articles, wrote the departments of history, of ancient philosophy, and of the mechanical arts. He also wrote art criticisms from 1765 to 1767, showing a readiness in interpreting the meaning of a picture, and a power in reproducing it vividly in words, any writer of his time. Towards the latter portion of his life, D.. who had never been able to save any money, determined to sell his library, to provide for his only daughter. The
empress Catherine of Russia, having been informed by her French ambassador of his intention, bought the library, on condition that D. himself should be librarian, and undertake the care of it at a salary of 1000 francs yearly. In 1778, he set out for St. Petersburg to thank his imperial benefactress, returning in the following year. But his health, which was impaired by this journey, soon after gave way, aud he died on the 30th July, 1784.
D. had worked at the encyclopaedia for the space of about 30 years. His fitness, natural and acquired, for this species of literarylabor was' complete. With the advantage of an excellent education, he had a great love of truth, and a curiosity to ascertain the real rela tions of any subject upon which he was engaged. He was distinguished by a swiftness and dexterity of intellect, that enabled him to catch the salient points of his topic, and to present them in the best light. As regards religion, D. was an atheist, sincere even to fanaticism in his opinions, and anxious to indoctrinate his countrymen with his own skepticism. The encyclopcedie became a vehicle for the indirect propagation of his views. One of the last recorded sayings of D. is very characteristic: "The first step towards philosophy is incredulity;" but, unfortnnately, D. thought it was also the last. An edition, in 20 volS., of all D.'s works, by Assezat and 'fourncux, was corn.
pleted in 1877. See John Morley's monograph on Diderot and the Encyclopedists (2 vols., 1878).
DIDdITS SALVIUS JULIANUS, MAncus, for a brief period emperor of Rome, under the name of Marcus Didius Commodus Severus Julianus. He was qumstor, redile, and prwtor; commanded a legion in Germany, and was governor of Belgic Gaul, and afterwards of Dalmatia and lower Germany. He was consul and proconsul in Africa, and governor of Bythinia in Asia Minor. When PertinaA: was assassinated, the throne was offered to the highest bidder by the prfetorians, and Didius bought it, thus becom ing emperor; but whenever he appeared in the streets he was greeted with the epithets of robber " and "parricide." The legions abroad did not recognize him, and proclaimed Septinms Severus as the true emperor. Severns marched to Rome and was recognized by the senate. Didius was deserted, and after two months' reign was killed by a soldier.