539465 JJ (Joseph John) Thomson (1856-1940) British Nuclear physicist, discovered electron, here with his research students at the Cavendish Laboratory, Cambridge, in 1898.; (add.info.: Left to right, back row: SW Richardson, J Henry. Middle row : EBH Wade, GA Shakespear, CTR Wilson, Ernest Rutherford, W Craig-Henderson, JH Vincent, GB Bryan. Front row: J McClelland, C Child, Paul Langevin, JJ Thomson, J Zeleny, RS Willows, HA Wilson, JSE Townsend. ); Universal History Archive/UIG; out of copyright.