Sir John Sealy Edward Townsend, FRS (7 June 1868 – 16 February 1957) was an Irish-British mathematical physicist who conducted various studies concerning the electrical conduction of gases (concerning the kinetics of electrons and ions) and directly measured the electrical charge. He was a Wykeham Professor of physics at Oxford University. The phenomenon of the electron avalanche was discovered by him, and is known as the Townsend discharge. Source: Wikipedia (en)