Bragg, Sir William Henry, 1862-1942. Knight. Physicist.

William Henry Bragg was born in Westward, Cumberland, the son of Robert John Bragg, a farmer, and Mary Wood in 1862. He was educated at Market Harborough and attended King William's College on the Isle of Man. In 1881 he went to Trinity College, Cambridge to study Mathematics. In 1884 he was third wrangler in part one of the Tripos and gained a first in part 3 of the Mathematical Tripos in 1885. In 1886 he became Elder Professor of Mathematics and Physics of the University of Adelaide and moved to Australia. In 1889 he married Gwendoline Todd and they had three children, William Lawrence, Robert Charles and Gwendoline Mary. He did not undertake much research until after addressing some scientific people in the country about current and past research in 1904. With the assistance of R. D. Kleeman, he decided to research into the radiations of electrons, x-rays, radioactivity and the extent to which they were absorbed and scattered by gases and solids. He discovered that alpha-particles of radium were ceased in ionisation. In 1903 he became President of Section A of the Australian Association for the Advancement of Science. In 1907 he became a Fellow of the Royal Society. In 1909 he returned to England as Cavendish Professor of the University of Leeds which he held until 1915. In 1912 Max Von Laue showed that x-rays are diffracted by the atoms of a crystal. Using ionisation on such work and working with his son, William Lawrence Bragg (known as Lawrence in order to distinguish him from his father), they developed the science of x-ray crystallography. In 1913 he used ionisation to reflect x-rays and together with his son Lawrence, published "X-Rays and Crystal Structure" in 1915. He won the Nobel Prize for physics with Lawrence in 1915. He also gained several medals for his work on x-rays and crystallography, such as the Rumford medal in 1916 and the Copley medal in 1930 from the Royal Society, and the Faraday medal in 1936 from the Institution of Electrical Engineers. From 1915 to 1923, he was the Quain Professor of Physics at the University of London. During the First World War, he worked on underwater acoustics for the Admiralty in order to detect submarines. He was knighted in 1920. He became Fullerian Professor of Chemistry and Director of the Davy-Faraday Research Laboratory at the Royal Institution of Great Britain (RI) in 1923. He was known as a good lecturer and had many of his lectures published for example: The World of Sound in 1920 and Concerning the Nature of Things in 1925, which were taken from his Christmas Lectures given at the RI. He published papers such as `On the Absorption of X-rays and the Classification of the X-rays in Radium' in Philosophical Magazine in 1904, and others in Nature, Proceedings of the Royal Society and Transactions Royal Society South Australia; and books such as Crystallography and X-Rays and Crystal Structure. In 1932 he became President of the Physical Society. In 1935 he became President of the Royal Society. He died at the RI, London, in 1942.