down to ataxic fever. The republic pensioned his widow. He introduced numerous improvements in surgical instruments and their use, especially for the treatment of fractures and ligature of arteries. In conjunction with his friend Chopart, he wrote the Traité des maladies chirurgicales (2 vols. 8vo, 1780), which has been translated into English by Trumbull. His Euveres chirurgicales were published by Bichat (8 vols. 8vo, 1798-'9).
DES BARRES, Joseph Frederick Wallet, an English soldier and hydrographer, born in 1722, died in Halifax, N. S., Oct. 24, 1824. He was descended from a French family which emigrated to England after the revocation of the edict of Nantes. Graduating from the royal military college at Woolwich, he embarked in March, 1756, as lieutenant in the 60th regiment of foot, for America. Having raised more than 300 recruits in Pennsylvania and Maryland, he formed them into a corps of field artillery, which he commanded until the arrival of one of the battalions of the royal train from England. In 1757 he commanded a detachment of volunteers against the Indians, who had committed depredations in the neighborhood of Schenectady and other frontier towns, and not only defeated them, but won them over to the assistance of the English. In 1758 he was engaged in the expedition against Louisburg, where he did good service; and after the capitulation he drew up a chart of the St. Lawrence, which was useful in the campaign of the next year. At the siege of Quebec he was aide-de-camp to Gen. Wolfe, and was making his report when that hero received his mortal wound, and fell dying in his arms. In 1760 and subsequently he conducted the operations for the defence of Quebec and the other places acquired by the British, as well as those for the reduction of Fort Jacques Cartier and others that still held out, thus completing the conquest of Canada. He was afterward ordered to Nova Scotia to assist Gen. Bastide in tracing designs and making estimates of the expense for fortifying the harbor of Halifax, and securing its dockyard. In 1762 he served as directing engineer and quartermaster general in the expedition for retaking Newfoundland, and received public thanks for his service in the recovery of that island. After making surveys of some of its principal harbors, he was ordered to New York, to proceed on reconnoitring excursions and report observations on the expediency of establishing a chain of military posts throughout the British colonies. In 1768 Lord Colville received instructions to employ him on the survey of the coast of Nova Scotia, in which he was engaged till 1773. The want of correct charts of the coast of North America for the fleet engaged in carrying on the American revolutionary war being severely felt, he was selected to adapt the surveys of Holland, De Brahm, and others to nautical purposes. These he published in 1777 under the title of "The Atlantic Neptune," in two large folio volumes. In 1784 he was appointed governor of the island of Cape Breton, and military commander of that and of Prince Edward island; and soon afterward he commenced building the town of Sydney, and opened and worked the valuable coal fields at the entrance of the river. In 1804 he was appointed lieutenant governor and commander-in-chief of Prince Edward island, being then in his 82d year. In person he was short, and at the age of 95 lithe and active. He was Capt. Cook's teacher in navigation.
DESCARTES, René (Lat. RENATUS CARTESIUS), a French philosopher, born at La Haye, Touraine, March 31, 1596, died in Stockholm, Feb.11, 1650. He was the youngest son of a councillor of the parliament of Rennes, of an ancient and noble family, and early in life evinced such a disposition to inquire into the nature and causes of things, that he was called the young philosopher. His education was conducted in the Jesuit college of La Flèche, where he made rapid progress in the Greek and Latin classics, and the other ordinary studies of such an institution. He contracted also while there a friendship with Mersenne, which lasted until the end of his life; and though Mersenne became a monk, it was chiefly through him that Descartes communicated, from his profound scholastic retirement, with the outside learned world. After leaving college, in his 16th year, he occupied himself in preparing for the military life to which he was destined by the wishes of his family and the spirit of the times. But his health being delicate, he was sent to Paris with a tutor, to pass two years in the further prosecution of his studies. In 1616 he joined the army of Maurice of Nassau, and while in garrison at Breda composed his Compendium Musicæ, which seemed a prelude to the research for harmony which he was soon about to carry into all the realms of knowledge. He was driven to it, doubtless, by the painful uncertainty and chaotic confusion which reigned in nearly all the departments of human inquiry. He was troubled by the doubts of his epoch, but he shared also in its grand hopes. In 1619 he left the Dutch army, and entered as a volunteer the service of Maximilian of Bavaria, the head of the Catholic league; he was present at the battle of Prague in 1620, and made with the imperialists the campaign of Hungary in 1621. The atrocities which he witnessed in this war are said to have been the occasion of his resigning his commission. After visiting the greater part of the north of Europe, he returned to France, sold his estates, and speedily resumed his journeys. He spent some time in Switzerland and Italy, being present at Rome during the jubilee of 1625, and wherever he went observing the phenomena of nature, and perfecting himself in the acquisition of knowledge. At Neuburg, on the Danube, where he passed the winter,the plan of devoting the remainder of his days to the reconstruction of the principles of hu-
