DUDDELL, WILLIAM DU BOIS British electrical engineer, was born in 1872. Because of his delicate health Duddell was educated at Cannes, and as a child he showed signs of great mechanical ingenuity. He served his apprenticeship as an engineer at Colchester. In 1893 he went to the City and Guilds Institute, where he stayed for some years because of the facilities for experimental work. Later he had an office of his own in Victoria street, London. Duddell showed an extraordinary gift for designing and constructing apparatus. His first, and probably his most notable instrument was the Duddell galvanom eter or oscillograph. (See INSTRUMENTS, ELECTRICAL.) While carrying out observations on the resistance of the electric arc, the results of which were published in the Proceedings of the Royal Society (1901), he discovered the "singing arc," which led even tually to the development of the Poulsen arc. In connection with this work he designed and constructed a mechanical high fre quency alternator giving 120,000 cycles per sec. Duddell also designed a thermo-ammeter (see INSTRUMENTS, ELECTRICAL), which he used in his work on radio-telegraphy. He was F.R.S. and held office in several learned societies. Duddell died on Nov. 4,