J. J. Thompson

The lectures were published as discharge of electricity through gases (1897). He even wrote an autobiography "Recollections and Reflections" in 1936. He did this by using magnetic and electric fields to deflect the stream of positive ions of neon gas onto two different types of a photographic plate. He led Great Britain to dominance in the field of subatomic particles in the early decades of the 20th century. He discovered a method for separating different kinds of atoms and molecules by the positive rays, and idea developed by Aston, Dempster and others towards the discovery of many isotopes. Thomson subsequently turned his attention to positively charged ions. Seven of his research assistants including his son, George, won Nobel Prizes for physics.

In 1896, Thomson visited America to give a course of four lectures, which summarized his current researches at Princeton. The demonstration clearly pointed to the possibility that ordinary elements might exist as isotopes (varieties of atoms of the same element, which have the same atomic number but different mass. His research showed that neon gas was made up of a combination of two different types of ion, each with different charge, mass, or both. An original study of cathode rays culminating in the discovery of the electron, this was announced to the royal.