CROOKES, kroks. Sir WILLIAM (1832—). An English physicist and chemist, horn in Lon don. He studied chemistry, and later assisted Hofmann at the Royal College of Chemistry. In 1854 lie became superintendent of the meteo•° logical department of the Radcliffe Observatory, Oxford, and in 1855 professor of chemistry at the Chester Training College. lie is the editor and proprietor of the Chemical News, xvhiel) founded in 1859, and has edited the Quarterly Journal of Science since 1864. Ile has been a fellow of the Royal Society since 1863. and was knighted in 1897. He is an authority of the first rank on sanitary questions. especially the disposal of the sewage of towns, and his method of producing extreme vacua rendered incan descent electric lighting a practical possibility. His original researches in chemistry and physics led to the discovery of the metal thallium in Subsequentiv he devoted several years to an elaborate investigation on the atomic weight of that element. Among his other discoveries
may be mentioned the sodium amalgamation process for separating gold and silver from their ores (1865), and especially his new method for the spectroscopic investigation of substances— one of the numerous and brilliant results of his prolonged studies of 'radiant matter.' He also devised the radiometer (q.v.). and later the otheoscope, a greatly improved form of the radiometer. Among his publications may be mentioned: .1 Practical Handbook of Dyeing and Calico Printing (2d ed., 1883); Setret Methods of Chemical Analysis (4th ed.. 1894) ; an Eng lish translation of Wagner', Chcmicol Technol ogy (2d ed., 1894) ; and papers on radiant-nmtter spectroscopy. His original views on the genesis of the elements may, with the development of knowledge, form an important contribution to chemical philosophy.