Duchesne, or Du Chesne (du˙-shān), André, French historian, born in 1584, died in 1640. His most important works are his collection of French historians—Historiæ Francorum Scriptores; Historiæ Normanorum Scriptores 838-1220; Histoire d'Angleterre, d'Écosse, et d'Irlande; Histoire des Papes.
Ducis (dü-sēs), Jean François, French dramatic writer, born at Versailles 1733, died 1816. Of his original works, the tragedy Abufar was much admired; but he is now best known for his adaptations of Shakespeare to the Parisian stage.
Duck, the name given to web-footed birds constituting the sub-family Anatinæ of the family Anatidæ, which also includes swans and geese. The ducks are very numerous as species, and are met with all over the world. They are often migratory, going northward in summer to their breeding-places. Their food is partly vegetable, partly animal. The common mallard or wild-duck (Anas boschas) is the original of the domestic duck. In its wild state the male is characterized by the deep green of the plumage of the head and neck, by a white collar separating the green from the dark chestnut of the lower part of the neck, and by having the four middle feathers of the tail recurved. The wild-duck is taken in large quantities by decoys and other means. Some tame ducks
have nearly the same plumage as the wild ones; others vary greatly, being generally duller or pure white, but all the males have the four recurved tail-feathers. There are several favourite varieties of the domestic duck, those of Normandy and Picardy in France, and the Aylesbury ducks in England, being remarkable for their great size and delicacy of flesh. Other species of the sub-family are: shoveller (Spatula clypeata), garganey (Querquedula circia), pintail or sea-pheasant (Dafila acuta), teal (Nettion crecca), widgeon (Mareca penelope), gadwall (Chaulelasmus streperus), sheldrake (Tadorna cornuta), tree-ducks (species of Dendrocygna). In a wider sense the name 'duck' is applied to species of other sub-families of the Anatidæ as follows: Merganettinæ: blue duck (Hymenolæmus malacorhynchus) of New Zealand. Erismaturinæ: musk duck (Biziura lobata) of Tasmania and Australia. Lake ducks (species of Erismatura). Fuligulinæ: eider duck (Somateria mollissima), q.v.; scoter or black duck (Œdemia nigra); harlequin duck (Cosmonetta histrionica); logger-head or steamer duck (Tachyeres cinereus) of South America: scaup (Fuligula marila); canvas back (F. vallisneria), q.v.; pochard (Nyroca ferina). Plectopterinæ: summer duck (Aix sponsa) of N. America and Cuba; mandarin duck (A. galericulata) of E. Asia; Muscovy or musk duck (Cairina moschata), ranging from Mexico to the Argentine.—Bibliography: Nourse, Turkeys, Ducks, and Geese; Rankin, Natural and Artificial Duck Culture; J. G. Millais, British Diving Ducks.
Ducking-stool, a stool or chair in which common scolds were formerly tied and plunged into water. They were of different forms, but that most commonly in use consisted of an upright post and a transverse movable beam on which the seat was fitted or from which it was suspended by a chain. The ducking-stool is mentioned in Domesday Book (Chester): it was extensively in use throughout the country from the fifteenth till the beginning of the eighteenth century, and in one case—at Leominster—was used as late as 1809.
Duckweed, the popular name of several species of Lemna, nat. ord. Lemnaceæ, plants growing in ditches and shallow water, floating on the surface, and serving as food for ducks and geese. Five species are known in Britain, and others are common in America. They consist of small fronds bearing naked unisexual flowers.
Duckworth, Sir John Thomas, a British admiral, born in 1748, died 1817. He joined the navy when eleven years of age; and was post-captain in 1780. In 1793, on the breaking out of the French war, he was appointed to the command of the Orion, 74, forming part of the Channel fleet under Lord Howe, and distinguished himself in 1794 in the great naval victory on 1st June. In 1798 he aided in the capture of Minorca. From 1800 to 1806 he rendered important services on the West India station, in particular gaining a complete victory over a French squadron, for which he received a pension of £1000 a year and the thanks of both Houses of Parliament. In 1807, having been ordered to Constantinople, he forced the passage of the Dardanelles, but suffered severely from the Turkish batteries in returning. From 1810 to 1814 he commanded the Newfoundland fleet, and in 1817 he was appointed to the chief command at Plymouth. In 1813 he was created a baronet.
Duclos (du˙-klō), Charles Pinot, a French novelist, writer of memoirs, and grammarian, born in 1704 at Dinant, died at Paris 1772. He became secretary of the French Academy, and on the resignation of Voltaire he was appointed to the office of historiographer of France. His writings are lively and satirical. Among the best are: Confessions du Comte de * * * (1741), Considérations sur les Mœurs de ce Siècle, Mémoires secrets sur les Règnes de Louis XIV et XV, and Remarques sur la Grammaire générale de Port-Royal.
Ductil´ity, the property of solid bodies, particularly metals, which renders them capable of being extended by drawing, while their thickness or diameter is diminished, without any actual fracture or separation of their parts. The following is nearly the order of ductility of the metals which possess the property in the highest degree, that of the first mentioned being the greatest: gold, silver, platinum, iron, copper,