BRAGG, SIR WILLIAM HENRY (1862- ), British physicist, was born at Wigton, Cumberland, July 2, 1862, and was educated at King William's college, Isle of Man, and Trinity college, Cambridge. In 1886 he was appointed professor of math ematics and physics at Adelaide, South Australia, where he carried out his earlier researches in radio-activity. In 1909 he was ap pointed Cavendish professor at Leeds and in 1915 Quain professor of physics in the University of London. His researches upon va rious radio-active phenomena and his power of lucid exposition brought recognition from scientific bodies both at home and abroad; in 1906 he was elected a fellow of the Royal Society; in 1915 he received the Nobel Prize for physics and the Barnard Gold Medal (Columbia university), both of which distinctions he shared with his son William Lawrence Bragg (b. 1890). • The joint work of father and son went far towards elucidating the arrangements of atoms and crystals, an achievement rendered possible by their development of the X-ray spectrometer. During the World War Sir William Bragg acted in an advisory capacity to the British Admiralty, especially with regard to the problem of submarine detection. He was created K.B.E. in 192o. In the same year he was elected an honorary fellow of Trinity college, Cam bridge, and was president of the Physical Society of London. In 5923 he was appointed Fullerian professor of chemistry at the Royal Institution and director of Davy-Faraday research labo ratory; and subsequently director of the Royal Institution.
Sir William Bragg was elected president of the British Associ ation for the Advancement of Science in 1928, succeeding Sir Arthur Keith.