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will-o'-the-wisp

(Encyclopedia)will-o'-the-wisp, phenomenon known also as ignis fatuus and jack-o'-lantern. It is seen at night as a pale, flickering light over marshland. There is no generally accepted explanation for it; it may r...

septic tank

(Encyclopedia)septic tank, underground sedimentation tank in which sewage is retained for a short period while it is decomposed and purified by bacterial action. The organic matter in the sewage settles to the bott...

expansion

(Encyclopedia)expansion, in physics, increase in volume resulting from an increase in temperature. Contraction is the reverse process. When heat is applied to a body, the rate of vibration and the distances between...

Compton, Karl Taylor

(Encyclopedia)Compton, Karl Taylor, 1887–1954, American physicist, b. Wooster, Ohio, grad. College of Wooster (Ph.B., 1908), Princeton (Ph.D., 1912); brother of A. H. Compton. He taught at Princeton from 1915 to ...

safety lamp

(Encyclopedia)safety lamp, oil lamp designed for safe use in mines and other places where flammable gases such as firedamp (see damp) may be present. Its invention (c.1816) is usually attributed to Sir Humphry Davy...

correspondence principle

(Encyclopedia)correspondence principle, physical principle, enunciated by Niels Bohr in 1923, according to which the predictions of the quantum theory must correspond to the predictions of the classical theories of...

Fisher, Irving

(Encyclopedia)Fisher, Irving, 1867–1947, American economist, b. Saugerties, N.Y., Ph.D. Yale, 1891. He began teaching at Yale in 1890 and was active there until 1935. His earliest work was in mathematics, and he ...

boiler

(Encyclopedia)boiler, device for generating steam. It consists of two principal parts: the furnace, which provides heat, usually by burning a fuel, and the boiler proper, a device in which the heat changes water in...

Reidsville

(Encyclopedia)Reidsville rēdsˈvĭl [key], industrial city (1990 pop. 12,183), Rockingham co., N N.C.; settled c.1815, inc. 1873. It is a tobacco center, and manufactures include industrial gases; metal, concrete,...

convection

(Encyclopedia)convection, mode of heat transfer in fluids (liquids and gases). Convection depends on the fact that, in general, fluids expand when heated and thus undergo a decrease in density (since a given volume...