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Witz, Conrad

(Encyclopedia)Witz, Conrad kônˈrät vĭts [key], fl. c.1434–c.1447, German painter, active at Basel and Geneva. Many of the works attributed to him, such as The Synagogue and the Meeting of Joachim and Anna, ca...

radioactivity

(Encyclopedia)CE5 Effects of a magnetic field on the products of radioactivity CE5 Disintegration series: Radioactive decay of radium-226 into lead-206 radioactivity, spontaneous disintegration or decay of t...

Stefan, Josef

(Encyclopedia)Stefan, Josef yōˈzĕf shtĕfˈän [key], 1835–93, Austrian physicist. At the Univ. of Vienna he became a professor of physics and later director of the Physical Institute. From his observations on...

Abbot, Charles Greeley

(Encyclopedia)Abbot, Charles Greeley, 1872–1973, American astrophysicist, b. Wilton, N.H. He was acting director in 1896 and director in 1907 of the astrophysical observatory of the Smithsonian Institution; he wa...

ultraviolet astronomy

(Encyclopedia)ultraviolet astronomy, study of celestial objects by means of the ultraviolet radiation they emit, in the wavelength range from about 90 to about 350 nanometers. Ultraviolet (UV) line spectrum measure...

ozone layer

(Encyclopedia)ozone layer or ozonosphere, region of the stratosphere containing relatively high concentrations of ozone, located at altitudes of 12–30 mi (19–48 km) above the earth's surface. Ozone in the ozone...

Walker, Robert

(Encyclopedia)Walker, Robert, d. 1658?, English painter, a follower of Van Dyck and favorite portraitist of Oliver Cromwell. His portraits of Cromwell and his family and followers are convincing studies of Puritan ...

Dutch and Flemish literature

(Encyclopedia)Dutch and Flemish literature, literary works written in the standard language of the Low Countries since the Middle Ages. It is conventional to use the term Dutch when referring to the language spoken...

White, Hugh Lawson

(Encyclopedia)White, Hugh Lawson, 1773–1840, American political leader, b. Iredell co., N.C. He moved (1787) to what is now E Tennessee and served in the wars against the Creek and Cherokee. He was (1793) secreta...

Randall, John Ernest, Jr.

(Encyclopedia)Randall, John Ernest, Jr., 1924–2020, American ichthyologist, b. Los Angeles, Ph.D. Univ. of Hawaii, Manoa, 1955. A marine taxonomist, he named 30 new genera and hundreds of new species of fish. Par...