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echo sounder

(Encyclopedia)echo sounder, an older instrumentation system for indirectly determining ocean floor depth. Echo sounding is based on the principle that water is an excellent medium for the transmission of sound wave...

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...

Sture

(Encyclopedia)Sture stüˈrə [key], noble family that played a leading role in Sweden in the 15th and 16th cent. Sten Sture, the elder, c.1440–1503, was chosen regent in 1470. In the battle of Brunkeberg (1471) ...

tachyon

(Encyclopedia)tachyon tăkˈēŏnˌ [key], hypothetical elementary particle that travels only at speeds exceeding that of light. According to the theory of relativity, the speed of light is the limiting velocity fo...

will, in philosophy and psychology

(Encyclopedia)will, in philosophy and psychology, term used to describe that which is alleged to stimulate the motivation of purposeful activity. It is characteristic of the will that it can be observed only in one...

Wilson, William Lyne

(Encyclopedia)Wilson, William Lyne, 1843–1900, American legislator, cabinet member, and university president, b. Jefferson co., Va. (now in W.Va.). He was a private in the Confederate army in the Civil War, and a...

wormwood

(Encyclopedia)wormwood, Mediterranean perennial herb or shrubby plant (Artemisia absinthium) of the family Asteraceae (aster family), often cultivated in gardens and found as an escape in North America. It has silv...

Blanc, Louis

(Encyclopedia)Blanc, Louis lwē bläN [key], 1811–82, French socialist politician and journalist and historian. In his noted Organisation du travail (1840, tr. Organization of Work, 1911), he outlined his ideal o...

lever

(Encyclopedia)CE5 Classes of levers: A first-class lever (A), a second-class lever (B), and a third-class lever (C) lever, simple machine consisting of a bar supported at some stationary point along its length ...

radar

(Encyclopedia)radar, system or technique for detecting the position, movement, and nature of a remote object by means of radio waves reflected from its surface. Although most radar units use microwave frequencies, ...