Page:Encyclopædia Britannica, Ninth Edition, v. 7.djvu/538

518 , and was created duke of Moliuas. In May , at the command of Charles V., who named him constable of France, he returned to France. War had just been declared against England, and Du Guesclin was called to take part in it. For nearly ten s he was engaged in fighting against the English in the south and the west of France, recovering from thorn the provinces of Poitou, Guieune, and Auvergne, and thus powerfully contributing to the establishment of a united France. In, when the duke of Brittany sought English aid against a threatened invasion by Charles V., Du Guesclin was sent at the head of a powerful army to seize the duchy, which he did ; and two years later he frustrated by a defensive policy the attempt of the duke with an English army to recover it. Finding in that the king entertained suspicions of his fidelity to him, he resolved to give up his constable s sword and retire to Spain. His resolution was at first proof against remonstrance ; but ultimately he received back the sword, and continued in the service of France. In he was sent into Languedoc to suppress disturbances and brigandage, provoked by the harsh government of the duke of Aujou. His first act was to lay siege to the fortress of Chateauueuf-Iiandon, held by the English, strongly garrisoned and well provisioned. A day was fixed con ditionally for capitulation. Meanwhile the great warrior was smitten with a mortal illness, and died, July 13,. The commander led out the garrison and deposited the keys of the castle on the coffin of the hero. Du Guesclin lost his first wife in, and married a second in , but he left no legitimate children. His remains were interred, by order of the king, in the church of St Denis.

1em  DUHALDE, (–), geographical writer, was born at Paris, February 1,. In he entered into the Society of Jesus, and some time afterwards he was appointed to succeed Father Legobien, who had been intrusted with the duty of collecting and arranging the letters which they received from their missionaries in different quarters of the globe. He was also for some time secretary to the famous Father Le Tellier, confessor to the king of France. He died August 18,. Duhalde is represented as a man of mild and amiable character, and as remarkable alike for his unaffected piety and unwearied industry. He was the author of some Latin poems, which do nob evince any superior degree of excellence. The productions for which he is principally distinguished are (1) Lettres Edifiantes et Gurieuses ecrites des Missions Etrangeres, which he edited with great ability from the ninth to the twenty-sixth volume inclusive, and which have been translated into English and German; and (2) Description geographique, historique,chronologique, politique, et physique de I Empire de la Chine et de la Tartarie Chinoise, Paris,, in four volumes large folio, with figures and an atlas by D Anville. This work, the first in which China is described with so much exactness and detail, is a beautiful specimen of French typography. An English translation by Brookes was published in in 4 vols.  DUHAMEL, (–), a French astronomer and physician, was the son of an advocate, and was born at Vire, in Normandy, in. He commenced his studies at Caen, and completed them at Paris. At the age of eighteen he wrote a treatise on the Spherics of Theodosius, and added to it a tract on trigonometry, designed as an introduction to astronomy. At the age of twenty-one he became cure&quot; of Neuilly-sur-Marne, but with out neglecting the duties of his calling, he continued to cultivate the physical sciences with zeal. In 1656 he was named almoner of the king; in he obtained trig dignity of chancellor of the church of Bayeux ; and in, when Louis XIV. established the Royal Academy of Sciences, he was appointed perpetual secretary. He was preparing a history of the Academy when he died, August 6, . He published numerous works on philosophy, divinity, and physical science.  DUHAMEL DU MONCEAU, (–), a celebrated French botanist and agriculturist, was the son of Alexandre Duhamel, loid of Deuainvilliers, and was born at Paris in. He was placed at the College d Harcourt, but made little progress in his studies, except that, notwithstanding the imperfect manner in which the natural sciences were there taught, he acquired such a taste for these branches of knowledge as led him to attend the lessons of Dufay and Bernard de Jussieu at the Jardin des Plantes. He now spent his time between the capital, where he pursued his botanical studies and held intercourse with scientists, and his estates at Gatinais, where he employed his knowledge in arboricultural experiments. Having been requested by the Academy of Sciences to investigate the cause of the disease which was destroying the saffron plant in Gatinais, he discovered that its destruc tion was owing to a parasitical fungus which attached itself to its roots. The work in which he demonstrated his dis covery was judged worthy to appear in the transactions of the Academy, and gained him admission to that body in . From then until his death he busied himself chiefly with making experiments in vegetable physiology, and recording and publishing his observations. Having learned from Sir Hans Sloane that madder possesses the property of giving colour to the bones, he fed animals successively on food mixed and unmixed with madder ; and he found that their bones in general exhibited concentric strata of red and white, whilst the softer parts showed in the mean time signs of having been progressively extended. From a number of experiments ho was led to believe himself able to explain the growth of bones, and to demonstrate a parallel between the manner of their growth and that of trees. Along with the celebrated naturalist Buffon, he made numerous experiments on the growth and strength of wood, one of the results of which was that he recommended the bark to be taken off the trees several years before they are cut down. He experimented also on the growth of the mistletoe, on layer planting, on smut in corn, and on the production of soda and potash by different vegetables. From the year he made meteorological observations, and kept records of the influence of the weather on agricultural production. Having been appointed inspector-general of marine, he applied his scientific acquirements to the improvement of nautical knowledge, subjecting everything to the test of facts and experiments. Duhamel s aim in his ressiarches was rather to be useful than to gratify his own curiosity or to win fame. He made himself accessible to all who sought information from him, and his modesty was as great as his knowledge. He was scrupulous in the practice of his religious duties. He died August 13,.

1em  DUISBURG, a town of Prussia, at the head of a circle hi the government of Diisseldorf, situated at an important railway junction in the country between the Rhine and the Ruhr, and communicating with both rivers by a canal. It has a fine Gothic church Saivatorkirche of the, a gymnasium, and an orphan asylum, and is also 