A D V E N T U R E S in C Y B E R S O U N DWilliam Crookes, Sir : 1832 - 1919
The English experimentalist William Crookes, (b. June 17, 1832, d. Apr. 4, 1919), contributed to many of the new fields of physics and chemistry that emerged in the late 19th century. His investigations of the photographic process in the 1850s motivated his work in the new science of spectroscopy. Using its techniques, Crookes discovered (1861) the element thallium, which won him election to the Royal Society. His efforts in determining the weight of thallium in an evacuated chamber led to his research in vacuum physics. Crookes invented the radiometer in 1875 and, beginning in 1878, investigated electrical discharges through highly evacuated "Crookes tubes." These studies laid the foundation for J. J. Thomson's research in the late 1890s concerning discharge-tube phenomena. At the age of 68, Crookes began investigating the phenomenon of radioactivity, which had been discovered in 1896, and invented a device that detected alpha particles emitted from radioactive material. Crookes maintained an interest in agriculture and warned in 1898 that the world's population would face starvation unless new fertilizer sources were discovered. He was also interested in psychic phenomena. He was knighted in 1897. Richard Hirsh
William Crookes, chemist and physicist, born in London. He studied at London, then superintended the meteorological department of the Radcliffe Observatory, Oxford, and from 1855 lectured on chemistry at Chester. In 1859 he founded the Chemical News, and edited it until 1906. He was an authority on sanitation, discovered the metal thallium (1861), improved vacuum tubes and promoted electric lighting, and invented the radiometer (1873-1876). He was knighted in 1897.
William Crookes, (b. June 17, 1832, London, Eng.--d. April 4, 1919, London), British chemist and physicist noted for his discovery of the element thallium and for his cathode-ray studies, fundamental in the development of atomic physics. After studying at the Royal College of Chemistry, London, Crookes became superintendentof the meteorological department at Radcliffe Observatory, Oxford, in 1854, and the following year gained a post at the College of Science in Chester, Cheshire. Having inherited a large fortune from his father, he devoted himself from 1856 entirely to scientific work of various kinds at his private laboratory in London. His researches on electrical discharges through a rarefied gas led him to observe the dark space around the cathode, now called the Crookes dark space. He demonstrated that cathode rays travel in straight lines and produce phosphorescence and heat when they strike certain materials. He invented many devices to study the behaviour of cathode rays, but his theory of radiant matter, or a fourth state of matter, proved incorrect in many respects. With the introduction of spectrum analysis by R.W. Bunsen and G.R. Kirchhoff, Crookes applied the new technique to the study of selenium compounds. In 1861 he discovered thallium in some seleniferous deposits. He continued work on that new element, isolated it, studied its properties, and in 1873 determined its atomic weight. During his studies of thallium, Crookes discovered the principle of the Crookes radiometer, a device that converts light radiation into rotary motion. The principle of this radiometer has found numerous applications in the development of sensitive measuring instruments. Crookes was knighted in 1897.
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