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Lenz's law

(Encyclopedia)Lenz's law, physical law, discovered by the German scientist H. F. E. Lenz in 1834, that states that the electromotive force (emf) induced in a conductor moving perpendicular to a magnetic field tends...

Leutze, Emanuel

(Encyclopedia)Leutze, Emanuel loitˈsə [key], 1816–68, American historical painter, b. Germany. In 1859 he settled in the United States, working in Washington, D.C., and New York City. His pictures are chiefly E...

Jocelin de Brakelond

(Encyclopedia)Jocelin de Brakelond jŏsˈlĭn də brākˈlŏnd [key], fl. 1200, English chronicler, a monk of Bury St. Edmunds. His chronicle of St. Edmund's Abbey, covering the years 1173–1202, is written in a s...

ratchet and pawl

(Encyclopedia)ratchet and pawl, mechanical device that permits motion in one direction only. The ratchet is usually a wheel with slanting teeth. The pawl is a lever tangential to the wheel with one end resting on t...

motor, electric

(Encyclopedia)CE5 Motor: In the AC motor, current fed to the conducting loop of wire causes it to rotate in the magnetic field, thus turning the shaft on which the loop is mounted. In the DC motor, the direction...

Van Dyck, Sir Anthony

(Encyclopedia)Van Dyck or Vandyke, Sir Anthony both: văn dīk [key], 1599–1641, Flemish portrait and religious painter and etcher, b. Antwerp. In 1618 he was received as a master in the artists' guild, but even ...

Democritus

(Encyclopedia)Democritus dĭmŏkˈrĭtəs [key], c.460–c.370 b.c., Greek philosopher of Abdera; pupil of Leucippus. His theory of the nature of the physical world was the most radical and scientific attempted up ...

airfoil

(Encyclopedia)airfoil, surface designed to develop a desired force by reaction with a fluid, especially air, that is flowing across the surface. For example, the fixed wing surfaces of an airplane produce lift, whi...

Lumière, Louis Jean

(Encyclopedia)Lumière, Louis Jean ōgüstˈ [key], 1862–1954, French inventors, brothers. They invented the Cinématographe, which was patented and demonstrated in 1895. This mechanism was the first to photograp...

Moretto, Il

(Encyclopedia)Moretto, Il ēl mōrĕtˈtō [key], c.1498–1554, Italian painter, whose real name was Alessandro Bonvicino. He was a leading representative of the Brescian school. While following the art of the Ven...