Lee De Forest (1873-1961), US inventor and electrical and radio engineer, with one of his inventions. De Forest studied at Yale, gaining his doctorate with a thesis on radio waves. In 1907 he patented the Audion tube (triode valve), a device that gained widespread use in radios to amplify weak signals. De Forest also invented and worked on a process to record sound directly onto film, a process he called Phonofilm, patented in 1919. This photograph is from the Bain News Service, one of the USA's earliest news picture libraries. The Bain News Service photographs date from the 1890s to the 1930s.