J. J. Thomson announces the electron at the Royal Institution

Background. The Royal Institution, founded in 1799, served as a hub for scientific education and research in London. Its mission included diffusing knowledge and facilitating the introduction of useful mechanical inventions through philosophical lectures and experiments. This institutional context provided the venue for Thomson's presentation, which aligned with the organization's foundational principles of applying science to common purposes.

Scientific Context. Prior to 1897, investigators like Heinrich Hertz believed cathode rays could not be deflected electrically. Thomson's work challenged this view by showing that cathode rays, then known as Lenard rays, could travel further through air than expected for atom-sized particles. This observation suggested the rays were composed of previously unknown negatively charged particles with a large charge-to-mass ratio.

Terminology. Thomson referred to the discovered particles as 'corpuscles' in his initial announcement. The term 'electron' had been suggested earlier by George Johnstone Stoney in 1891, prior to Thomson's experimental confirmation. While Thomson initially used 'corpuscles', later scientists preferred 'electron', a name that eventually became standard in physics.