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engraving

(Encyclopedia)engraving, in its broadest sense, the art of cutting lines in metal, wood, or other material either for decoration or for reproduction through printing. In its narrowest sense, it is an intaglio print...

elevator, in machinery

(Encyclopedia)elevator, in machinery, device for transporting people or goods from one level to another. The term is applied to the enclosed structures as well as the open platforms used to provide vertical transpo...

House Un-American Activities Committee

(Encyclopedia)House Un-American Activities Committee (HUAC), a committee (1938–75) of the U.S. House of Representatives, created to investigate disloyalty and subversive organizations. Its first chairman, Martin ...

Gay-Lussac, Joseph Louis

(Encyclopedia)Gay-Lussac, Joseph Louis zhôzĕfˈ lwē gā-lüsäkˈ [key], 1778–1850, French chemist and physicist. He was professor in Paris at the Sorbonne, at the Polytechnic School, and at the Jardin des Pla...

gas

(Encyclopedia)gas, in physics, one of the three commonly recognized states of matter, the other two being solid and liquid. A substance in the gaseous state has neither definite shape nor definite volume. Like liqu...

John II, king of Hungary and prince of Transylvania

(Encyclopedia)John II (John Sigismund Zapolya), 1540–71, king of Hungary and prince of Transylvania, son of John I. Through his mother, Isabel (daughter of Sigismund I of Poland), he was related to the Jagiello d...

microphone

(Encyclopedia)microphone, device for converting sound into electrical energy, used in radio broadcasting, recording, and sound amplifying systems. Its basic component is a diaphragm that responds to the pressure or...

melting point

(Encyclopedia)melting point, temperature at which a substance changes its state from solid to liquid. Under standard atmospheric pressure different pure crystalline solids will each melt at a different specific tem...

norepinephrine

(Encyclopedia)norepinephrine nôrˌĕpīnĕfˈrən [key], a neurotransmitter in the catecholamine family that mediates chemical communication in the sympathetic nervous system, a branch of the autonomic nervous sys...

luminescence

(Encyclopedia)luminescence, general term applied to all forms of cool light, i.e., light emitted by sources other than a hot, incandescent body, such as a blackbody radiator. Luminescence is caused by the movement ...