PICKERING, EDWARD CHARLES American physicist and astronomer, was born in Boston on July 19, 1846. He was graduated in 1865 in the Lawrence Scientific school of Harvard, where for the next two years he was a teacher of mathematics. Subsequently he became professor of physics at the Massachusetts Institute of Technology, where he established the first laboratory in America, in which students were instructed by actual contact with physical instruments and measurements. In 1876 he was appointed professor of astronomy and director at the Harvard college observatory. In 1877 when most observatories were devoting themselves to the old "astronomy of position" Prof. Pickering, who was a physicist rather than an old school astrono mer, chose as his particular field of labour the photometry of the stars, thus presaging the trend of the new astronomy along lines of physics. He invented the meridian photometers (see PHO TOMETRY: Stellar), with which the brightness of more than 45,00o stars has been measured at Cambridge and Arequipa (Peru) observatories, and the resulting system generally adopted as an international standard. Prof. Pickering, personally, made
more than 1,5oo,000 photometric settings.
Through the establishment of an observatory at Arequipa (1891), after two years of study it became possible to include measurements made on the stars throughout the Southern heavens within the scope of the Harvard college observatory's work.
The work of the observatory under Prof. Pickering may be summarized as including photometry, in which photometric mag nitudes for 8o,000 stars have been determined; a scale of photo graphic magnitude; a system of classification of variable stars; and a system of stellar spectroscopy which has been universally adopted. As a result of Pickering's work, the Harvard "pho tographic library" of stars contains more than 250,000 photo graphic plates. He died at Cambridge, Mass., on Feb. 3, 1919.
For bibliography and further biographical material see Biographical Memoirs of National Academy of Sciences, vol. vii., pp. See also Proceedings of the American Academy of Arts Sciences, vol. lvii., pp. (Boston, 1922) ; Monthly Notices of Royal Astronomy Society, vol. viii., pp.