Watteau \va-'to,\ English \wa-'to\, (Jean-) Antoine (b. Oct. 10, 1684, Valenciennes, France—d. July 18, 1721, Nogent-sur-Marne) French painter. Son of a roof tiler in Valenciennes, he was apprenticed to a local artist. At 18 he moved to Paris, where he worked for a series of painters; one of them was a theatrical scenery painter, and much of Watteau’s work consequently embraced the artifice of the theatre, particularly the comme- dia dell'arte and the ballet. His works typified the lyrically charming and graceful Rococo style. The greatest, his Pilgrimage to the Island of Cythera, depicts pilgrims setting out for (or departing from) the mythic island of love and was his presentation piece when he was inducted into the academy in 1717. The academicians, unable to fit him into any of the recognized categories, welcomed him as a painter of fetes galantes (“elegant festivities”), an important new genre to which countless later Rococo pictures belong.
wattle See acacia
Watts, Andre (b. June 20, 1946, Niimberg, Ger.) German-born U.S. pianist. Son of an African American soldier and a Hungarian mother, he made his debut at age nine at a Philadelphia Orchestra children’s concert. He attracted wide attention when at age 16 he performed on television
James Watt, oil painting by H. Howard; in the National Portrait Gal¬ lery, London.
COURTESY OF THE NATIONAL PORTRAIT GALLERY, LONDON
© 2006 Encyclopaedia Britannica, Inc.
Watts ► wax sculpture I 2037
under conductor Leonard Bernstein. Though already a mature musician, he chose to continue study with Leon Fleischer (b. 1928). In 1976 he gave a concert that was the first live television broadcast of a solo recital in history. His surpassing technique and understated manner made him a favoured concert performer, and his popularity continued into the 21st century.
Watts, Isaac (b. July 17, 1674, Southampton, Hampshire, Eng.—d. Nov. 25, 1748, Stoke Newington, London) English Nonconformist min¬ ister, regarded as the father of English hymnody. Watts studied at the Dis¬ senting Academy at Stoke Newington, London, and he later became pastor of Mark Lane Independent (i.e.. Congregational) Chapel. His collections of sacred lyrics include Horae Lyricae (1706), Hymns and Spiritual Songs (1707), and The Psalms of David Imitated in the Language of the New Testament (1719). His hymns, numbering more than 600, became known throughout Protestant Christendom; they include “When I Survey the Wondrous Cross,” “O God, Our Help in Ages Past,” “Joy to the World,” and “Jesus Shall Reign.” A man of great erudition, he published books on a range of subjects.
Watusi See Tutsi
wave Propagation of disturbances from place to place in a regular and organized way. Most familiar are surface waves that travel on water, but sound, light, and the motion of subatomic particles all exhibit wavelike properties. In the simplest waves, the disturbance oscillates periodically (see periodic motion) with a fixed frequency and wavelength. Mechanical waves, such as sound, require a medium through which to travel, while electromagnetic waves (see electromagnetic radiation) do not require a medium and can be propagated through a vacuum. Propagation of a wave through a medium depends on the medium’s properties. See also seismic WAVE.
wave In oceanography, a ridge or swell on the surface of a body of water, normally having a forward motion distinct from the motions of the par¬ ticles that compose it. Ocean waves are fairly regular, with an identifiable wavelength between adjacent crests and with a definite frequency of oscil¬ lation. Waves result when a generating force (usually the wind) displaces surface water and a restoring force returns it to its undisturbed position. Surface tension alone is the restoring force for small waves. For large waves, gravity is more important.
wave-cut platform or abrasion platform Gently sloping rock ledge that extends from the high-tide level at a steep cliff base to below the low-tide level. It develops as a result of wave abrasion; beaches pro¬ tect the shore from abrasion and therefore prevent the formation of plat¬ forms. A platform is broadened as waves erode a notch at the base of the sea cliff, causing overhanging rock to fall. As the sea cliffs are attacked, weak rocks are quickly eroded, leaving the more resistant rocks as pro¬ trusions.
wave front Imaginary surface that represents corresponding points of waves vibrating in unison. As identical waves from the same source travel through a homogeneous medium, corresponding crests and troughs are in phase at any instant; that is, they have completed the same fraction of their periodic motion. Any surface drawn through all points of the same phase constitutes a wave front.
wave function Variable quantity that mathematically describes the wave characteristics of a particle. It is related to the likelihood of the par¬ ticle being at a given point in space at a given time, and may be thought of as an expression for the amplitude of the particle wave, though this is strictly not physically meaningful. The square of the wave function is the significant quantity, as it gives the probability for finding the particle at a given point in space and time. See also wave-particle duality.
wave-particle duality Principle that subatomic particles possess some wavelike characteristics, and that electromagnetic waves, such as light, possess some particlelike characteristics. In 1905, by demonstrating the photoelectric EFFECT, Albert Einstein showed that light, which until then had been thought of as a form of electromagnetic wave (see electromagnetic radiation), must also be thought of as localized in packets of discrete energy (see photon). In 1924 Louis-Victor Broglie proposed that electrons have wave properties such as wavelength and frequency; their wavelike nature was experimentally established in 1927 by the demonstration of their diffraction. The theory of quantum electrodynamics combines the wave theory and the particle theory of electromagnetic radiation.
waveguide Device that constrains the path of electromagnetic waves (see electromagnetic radiation). It can be used to transmit power or signals in the form of waves while minimizing power loss. Common examples are metallic tubes, coaxial cables, and optical fibres (see fibre optics). Waveguides transmit energy by propagating transmitted electromagnetic waves through the inside of a tube to a receiver at the other end. Metal waveguides are used in such technologies as microwave ovens, radar sys¬ tems, radio relay systems, and radio telescopes.
wavelength Distance between corresponding points of two consecu¬ tive waves. “Corresponding points” refers to two points or particles that have completed identical fractions of their periodic motion. In transverse waves, wavelength is measured from crest to crest or from trough to trough. In longitudinal waves, it is measured from compression to com¬ pression or from rarefaction to rarefaction. Wavelength, X, is equal to the speed v of a wave in a medium divided by its frequency f or X = v/f
Wavell Vwa-val\ (of Eritrea and of Winchester), Archibald Percival Wavell, 1st Earl (b. May 5, 1883, Colchester, Essex, Eng.—d. May 24, 1950, London) British army officer. Recognized as an excellent trainer of troops, he became British commander in chief for the Middle East in 1939. In World War II he was noted for his defeat of the numerically superior Italian armies in North Africa (1940—41) but was unable to stop the German force under Erwin Rommel in the North Africa Campaign. As commander in chief of Southeast Asia (1941-43), he failed to stop the Japanese conquests of Malaya, Singapore, and Burma (1942). Promoted to field marshal, he served as viceroy of India (1943^-7).