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Pretorius, Andries Wilhelmus Jacobus

(Encyclopedia)Pretorius, Andries Wilhelmus Jacobus prĭtôrˈēəs, Du. änˈdrēs vĭlhĕlˈməs yäkōˈbəs prātôrˈēəs [key], 1799–1853, Boer (Afrikaner) leader. He was elected (1838) commandant general o...

Carrel, Alexis

(Encyclopedia)Carrel, Alexis kärĕlˈ, kə– [key], 1873–1944, American surgeon and experimental biologist, b. near Lyons, France, M.D. Univ. of Lyons, 1900. Coming to the United States in 1905, he joined the s...

pit bull

(Encyclopedia)pit bull, dog having a smooth coat, a stocky build, and a blocky head, originally bred for fighting from bulldog and terrier breeds. Pit bulls were used in bull- and bearbaiting for centuries and as g...

metamorphism

(Encyclopedia)metamorphism, in geology, process of change in the structure, texture, or composition of rocks caused by agents of heat, deforming pressure, shearing stress, hot, chemically active fluids, or a combin...

transmission

(Encyclopedia)transmission, in automobiles, system of parts connecting the engine to the wheels. Suitable torque, or turning force, is generated by the engine only within a narrow range of engine speeds, i.e., rate...

electrolyte

(Encyclopedia)electrolyte ĭlĕkˈtrəlītˌ [key], electrical conductor in which current is carried by ions rather than by free electrons (as in a metal). Electrolytes include water solutions of acids, bases, or s...

Crookes tube

(Encyclopedia)Crookes tube, device invented by Sir William Crookes (c.1875) consisting essentially of a sealed glass tube from which nearly all the air has been removed and through the walls of which are passed two...

Evans, Oliver

(Encyclopedia)Evans, Oliver, 1755–1819, American inventor, b. near Newport, Del. He joined his brothers in a flour-milling business in Wilmington, and after studying similar earlier devices, he developed, install...

Hasan

(Encyclopedia)Hasan häsänˈ [key], c.625–c.669; son of Ali and Fatima (daughter of Muhammad the Prophet). When Ali was killed in 661, Hasan became caliph, but he was not strong enough to withstand the threat of...

homogenization

(Encyclopedia)homogenization həmŏjˌənəzāˈshən [key], process in which a mixture is made uniform throughout. Generally this procedure involves reducing the size of the particles of one component of the mixtu...