Columbia Encyclopedia

Search results

272 results found

sundial

(Encyclopedia)sundial, instrument that indicates the time of day by the shadow, cast on a surface marked to show hours or fractions of hours, of an object on which the sun's rays fall. Although any object whose sha...

Lamont, Johann von

(Encyclopedia)Lamont, Johann von yōˈhän fən läˈmônt [key], 1805–79, Scottish-German astronomer and magnetician, b. Scotland. In 1817 he went to Ratisbon to study at the seminary. He remained in Germany to ...

Sheffield, city, England

(Encyclopedia)Sheffield, city and metropolitan borough (1991 pop. 470,685), N England, at the confluence of the Don River and four tributaries. Sheffield was one of the leading industrial cities of England. It has ...

Eudoxus of Cnidus

(Encyclopedia)Eudoxus of Cnidus yo͞odŏkˈsəs, nīˈdəs [key], 408?–355? b.c., Greek astronomer, mathematician, and physician. From the accounts of various ancient writers, he appears to have studied with Plat...

Greenwich mean time

(Encyclopedia)Greenwich mean time or Greenwich meridian time (GMT), the former name for mean solar time at the site of the Royal Observatory in Greenwich, England, which is located on the prime meridian. In 1925 th...

Pachuca de Soto

(Encyclopedia)Pachuca de Soto pächo͞oˈkä ᵺā sōˈtō [key], city (1990 pop. 174,013), capital of Hidalgo state, central Mexico, at the head of a ravine surrounded by foothills of the Sierra Madre Oriental. P...

Foucault, Jean Bernard Léon

(Encyclopedia)Foucault, Jean Bernard Léon zhäN bĕrnärˈ lāôNˈ fo͞okōˈ [key], 1819–68, French physicist. Known especially for his research on the speed of light, he determined its velocity in air and fou...

Dyson, Sir Frank Watson

(Encyclopedia)Dyson, Sir Frank Watson dīˈsən [key], 1868–1939, English astronomer, b. Ashby-de-la-Zouch, grad. Cambridge. He was astronomer royal of Scotland (1905–10) and of England (from 1910). As director...

Sitter, Willem de

(Encyclopedia)Sitter, Willem de vĭlˈəm də sĭtˈər [key], 1872–1934, Dutch astronomer and mathematician. He was professor from 1908 at the Univ. of Leiden and in 1919 became director of its observatory. His ...

Brashear, John Alfred

(Encyclopedia)Brashear, John Alfred brəshērˈ [key], 1840–1920, American maker of scientific instruments and educator, b. Brownsville, Pa. A mechanic by trade, he taught himself the art of making lenses and mir...