Tizard, Sir Henry Thomas, 1885–1959, English physical chemist and scientific adviser. He was educated at Westminster school and Magdalen College, Oxford, from which he received honors in natural science in 1908. During the years from the late 1920s to 1942, Tizard became an outstanding authority on aeronautics and championed the development of radar. His 1940 mission to Washington gave impetus to cooperation between scientists and the military in the United States. His own research concerned chemical indicators and aerodynamics, and his work on aircraft fuels led to the common use of octane ratings.