Joseph John Thomson (1856-1940), British physicist and Nobel laureate. Thomson is known for his discovery of the electron, which won him the 1906 Nobel Prize in Physics. Showing an early interest in atomic structure, he spent much of his life in the Cavendish laboratories in Cambridge, England. He made his discovery following a study of cathode rays, focused beams of charge in a vacuum. He concluded cathode rays were made up of 'corpuscles' originating from the atom. He postulated the 'plum pudding' atomic model, of electrons floating in positive charge, disproved in 1909. This portrait is from the Bain News Service, one of America's oldest news picture agencies, which holds images dating from the 1890s to the 1930s.