1 1 1 H 



Duckweed. A thick- 

 leaved variety, Lemna 

 gibba 



DUCKWEED 



It is the practice in some coun- 

 tries to mask the bows of the boat 

 with green leaves and branches ; 

 and in some instances decoy birds 

 (q.v.) are used to induce the wild 

 ducks to come near. See First Les- 

 sons in the Art of Wildfowling, 

 1896; Bird- raaMR^E^ra 

 Life of the 

 Borders, 2nd 

 ed. 1907, A. 

 Chapman. 



Duckweed 

 (Lemna). Ge- 

 nus of minute, 

 scale-like flow- 

 ering plants of 

 the natural 

 order Lemna- 

 ceae. They are 

 annual aquatic plants, floating on 

 the surface of ponds and ditches, 

 and consisting of a green disk, with 

 or without a simple root or roots. 

 They sometimes produce elemen- 

 tary flowers in the clefts of the 

 margin, but rarely seeds, and are 

 propagated by budding and by 

 bulbils which hibernate in the mud. 

 Duckworth, SIR DYCE (b. 1840). 

 British physician. Born Nov. 24, 

 1840, and educated at Liverpool, 

 he afterwards 

 studied medi- 

 cine at Edin- 

 burgh Univer- 

 sity and S 

 Bartholomew's 

 Hospital. After 

 a short time 

 (1864-65) as 

 assistant sur- 

 geon in the 

 navy, he set- 

 tled down to a 



Sir Dyee Duckworth, 

 Britis 



h physician 



Elliott Jk try 



consulting practice in London. He 

 was made consulting physician to 

 Edward VII, when prince of Wales, 

 treasurer and then senior censor 

 of the Royal College of Physicians, 

 and consulting physician to S. 

 Bartholomew's and the Seamen's 

 Hospitals. From 1904-10 he was 

 medical referee to the Treasury. In 

 1886 Duckworth was knighted, 

 and in 1909 was made a baronet. 



Duckworth, SIR JOHN THOMAS 

 (1748-1817). British sailor. Born 

 at Leatherhead, Feb. 28, 1748, he 

 entered the navy when 11 years old, 

 and was present at Quiberon Bay. 

 He then served in N. America and 

 the W. Indies, and was promoted 

 commander in 1780. Returning to 

 England in 1793, he was appointed 

 to the Orion, in which he greatly 

 distinguished himself at Ushant, 

 June 1, 1794. 



Knighted in 1801, in 1803 he was 

 commander-in-chief of Jamaica, 

 was promoted vice-admiral 1804, 

 and defeated the French off San 

 Domingo in 1806, for which he 

 received a j cnsion of 1,000 a year. 



Sir J. T. Duckworth, 

 British sailor 



From an engraving 



2708 



The following year he was sent to 

 Constantinople to dictate certain 

 conditions to the Porte. With the 

 assistance o f 

 the French, 

 the Turks had 

 strengthened 

 the fortifica- 

 tions of the 

 Dardanelles, 

 but Duck- 

 worth forced 

 the straits, 

 destroyed a 

 squadron o f 

 Turkish fri- 

 gates, and finally anchored 8 m. 

 from Constantinople, where he was 

 held up by wind and current, and, 

 his force being insufficient, he was 

 obliged to retreat. He was governor 

 of Newfoundland from 1810-13, 

 and was made a baronet in 1813. 

 He was appointed commander-in- 

 chief of Plymouth in Jan., 1817, 

 and died Aug. 31 of the same year. 



Duckworth, WYNTRID LAUR- 

 ENCE HENRY (b. 1870). British an- 

 thropologist and anatomist. Born 

 at Liverpool, June 5, 1870, and 

 educated at Birkenhead School, 

 Dinan, and Cambridge, he studied 

 medicine in Paris and London, and 

 anthropology in Paris. In 1898 he 

 became university lecturer in 

 physical anthropology at Cam- 

 bridge. He published Morphology 

 and Anthropology, 1904 ; Pre- 

 historic Man, 1912, etc. 



Duclaux, MADAME (b. 1857). 

 British poet and essayist. Born at 

 Leamington, Feb. 27, 1857, daugh- 

 ter of G. T. Robinson, she is also 

 known under her maiden name of 

 Agnes Mary Frances Robinson, as 

 Madame Darmesteter her first 

 husband was James Darmesteter 

 (q.v.) and as Madame Duclaux. 

 She married Emile Duclaux, direc- 

 tor of the Pasteur Institute, Paris, 

 in 1901. Her first volume, A Hand- 

 ful of Honeysuckle, appeared in 

 1878. Her Collected Poems, dis- 

 playing much lyrical charm, ap- 

 peared in 1901 ; in addition may be 

 noted studies of Emily Bronte, 

 Margaret of Angouleme, Mme. de 

 Sevigne, Renan, Twentieth Cen- 

 tury French Writers, 1914, and A 

 Short History of France, 1918. 

 Du Cros, WILLIAM HARVEY 

 (1846-1918). British business man. 

 Born June 19, 1846, he belonged to 

 a Huguenot family that had mi- 

 grated to Dublin from Montpellier 

 in 1702. He was educated for the 

 medical profession in Dublin, but 

 soon turned his attention to the 

 pneumatic tire industry, and later 

 became largely interested in the 

 motor industry. From 1906-8 

 he was Unionist M.P. for Hastings. 

 He died Dec. 21, 1918. Of his sons, 

 Arthur Philip was M.P. for Hast- 



DUDENEY 



ings, 1908-18, and then for the 

 Clapham division of Wandsworth. 

 In 1916 he was made a baronet. 

 A younger son, Alfred, was M.P. 

 for Bow and Bromley in 1910. 



Ducrow, ANDREW (1793-1842). 

 Equestrian performer and mimic. 

 Born in Southwark, Oct. 10, 1793, 

 the son of a celebrated strong man, 

 he was early trained to equestrian 

 and other circus feats. In 1808 he 

 was chief equestrian and rope- 

 dancer at Astley's ; and in 1813 

 gained fame as a pantomimist in 

 the part of Florio the dumb boy, 

 in The Forest of Bondy. After 

 touring the Continent, he returned 

 to Astley's, which he eventually 

 took over. On June 8, 1841, the 

 building was totally destroyed by 

 fire. His mind gave way under the 

 shock, and he died Jan. 27, 1842. 



Ductility. In metallurgy, the 

 general property of metals which 

 permits them to be drawn into rods 

 or wire. It is closely related to the 

 property of malleability, but it is 

 not quite the same ; though, as it 

 happens, gold and silver are at 

 once the two most malleable and 

 most ductile of all the metals. The 

 relative measure of the ductility 

 of a metal is determined by the 

 fineness of the wire down to which 

 it can be drawn; thus gold will 

 draw finer than platinum. The 

 metals rank as follows in order of 

 ductility: 1, gold; 2, silver; 3, 

 platinum ; 4, iron ; 5, nickel ; 6, 

 copper ; 7, zinc ; 8, tin ; 9, lead. 

 The ductility of iron is greatly in- 

 creased when the iron is converted 

 into steel ; and similarly many of 

 the copper alloys bronze, phos- 

 phor bronze, Delta metal, and 

 others, have greater ductility than 

 copper. See Metallurgy. 



Dudeney, MRS. HENRY (b. 

 1866). British novelist. Eldest 

 daughter of Frederick Whiffin, she 

 was born Oct. 

 21, 1866, and 

 educated a t 

 Hurstpier- 

 point, Sussex. 

 In 1884 she 

 was married to 

 Henry Ernest 

 Dudeney, au- 

 thor of The 

 Canterbury 

 P u z z 1 e s, 

 Amusements 

 in Mathematics, etc. Her novels 

 include A Man with a Maid, 1897 ; 

 The Maternity of Harriott Wicken, 

 1899; Folly Corner, 1899 ; Spindle 

 and Plough, 1901 ; The Story of 

 Susan, 1903; The Wise Woods, 

 1905 ; The Orchard Thief, 1907 ; 

 Married when Suited, 1911 ; Set 

 to Partners, 1913 ; The Secret Son, 

 1915 ; Travellers' Samples, 1916 ; 

 The Head of the Family, 1917. 



Mrs. Henry Dudeney, 



British novelist 



But tell 



