~~Sir+William+Crooke~~

[] Name: Sir William Crookes Date of birth and death: 1832-1919 Country of origin: England Discoveries: 1861 discovery of the element thallium, 1895 identified first helium sample, 1869 Crookes's invention of Crookes Tube

After studying at the Royal College of Chemistry,London, Crookes became superintendent of the meteorological department at Radcliffe Observatory, Oxford, in 1854, and the following year gained a post at the College of Science. Having inherited a large fortune from his father, he devoted himself from 1856 entirely to scientific work at his private laboratory in London. He invented many devices to study the behaviour of cathode rays, but his theory a fourth state of matter, proved incorrect. Crookes was knighted in 1897. In 1856 he married Ellen by whom he fathered three sons and a daughter.

In 1861, Crookes discovered a previously unknown element with a bright green emission line in its spectrum and named the element Thallium. Crookes also identified the first known sample of Helium in 1895. He was the inventor of the Crooke's tube which he developed in 1869. In 1895 he was the first scientist to identify the element Helium. He was a pioneer in the construction and use of vacuum tubes for the study of physical phenomena. He was one of the first scientists to investigate what is now called plasma. He also devised one of the first instruments for the study of nuclear radioactivity, the Spinthariscope. []