ABSTRACT
J.J. Thomson, best known today as the 'discoverer of the electron' was an important and pivotal figure in the history of British physics. His 35-yearlong professorship at the Cavendish Laboratory in Cambridge saw the Laboratory, and the generation of physicists he educated, break with nineteenth-century physical methods and concerns and become worldJeaders in the new twentieth-century physics with its concern for microphysics - elementary particles, atomic theory, the structure of light, etc. Thomson's own work marks the break with previous tradition, although his fundamental concepts remained rooted in his nineteenth-century background. To understand what he was doing when he 'discovered the electron' we have to look closely at his education and previous work, at how the electron work developed from his earlier studies, and at how it opened up new areas of physics.
