Background
Source: Wikipedia
Sir William Crookes (; 17 June 1832 – 4 April 1919) was an English chemist and physicist who attended the Royal College of Chemistry, now part of Imperial College London, and worked on spectroscopy. He was a pioneer of vacuum tubes, inventing the Crookes tube, which was made in 1875. Observing cathode rays generated in these tubes, Crookes posited that "radiant matter" was a unique fourth state of matter, a foundational contribution to plasma physics.
