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lamp,originally a vessel for holding oil or some combustible substance that could be burned through a wick for illumination; the term has been extended to other lighting devices. Stones, shells, and other objects of suitable shape were used for burning oil in the Paleolithic period. In Egypt and the Middle East saucerlike terra-cotta lamps were early known. In Greece torches were supplemented in the 6th cent. B.C. with pottery and metal lamps. The Greeks often used a cylindrical spout for the wick. The Romans used a superior closed type of lamp, often with multiple spouts. The float-wick lamp, in which the wick is supported above the oil, was probably of Egyptian origin; it survived in the West chiefly as a sanctuary lamp. The seven-branched candlestick of the Hebrews is believed to have been a support for a group of float-wick lamps. Its symbolical descendant is the eight-branched Hanukkah lamp, usually of the spouted saucer type. There was little improvement in the design of lamps from ancient times to the 18th cent. The Betty lamp of the North American colonists and pioneers was a spouted saucer lamp with a lid. Lamps were smoky because the center of the round wick received too little air for complete combustion. Flat wicks, introduced late in the 18th cent., made less smoke, but the light was somewhat dim. At about the same time a circular wick with an open center was invented by Aimé Argand, a Swiss chemist, who also introduced the glass lamp chimney. One- and two-burner lamps were common from the late 18th cent., and these often burned whale oil. Kerosene, used from the mid-19th cent., almost entirely superseded other oils for lamps; the kerosene lamp is still used for lighting where gas and electricity (the most common form of energy for lamps in industrialized countries) are not available and in many safety, signal, and hurricane lamps. In literature and art the lamp has often symbolized learning or knowledge; in religious ritual, honor to the divine. For the development of the electric lamp, see lightinglighting,
light produced by artificial means to allow visibility in enclosures and at night. For stage lighting, see scene design and stage lighting. Early Sources of Artificial Lighting
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See F. W. Robins, The Story of the Lamp (1939, repr. 1970); T. Szentléky, Ancient Lamps (tr. 1969); J. Paton, Lamps: A Collector's Guide (1979).
a light-producing device for the illumination of rooms, open spaces, or individual objects. Sometimes decoration is the main purpose of a lamp. Decorative lamps, however, in contrast to utilitarian lamps, do not play an important role in illumination. The first lamps were primitive oil lamps and wood splinters mounted in holders. Candles held in special vessels were another early type of lamp. The development of kerosine lamps and gas lamps was followed by the invention of modern electric luminaires with light sources in the form of incandescent lamps, fluorescent lamps, and high-pressure gas-discharge lamps (seeGAS-DISCHARGE LIGHT SOURCES).
The oldest lamps—shallow, concave stone vessels—have been found in cave dwellings of the Magdalenian culture of the Paleolithic. Aeneolithic lamps have been discovered that are made of clay; they are in the form of shallow dishes on saucers. In later periods lamps were developed with an enclosed reservoir that had two openings—one for the wick and one through which the lamp was filled with oil. Pottery or bronze lamps filled with olive oil were used in ancient Greece and Rome. Various kinds of lamps are known to have been used in the Middle Ages. Some lamps in ancient Rus’ were of a multilevel design —several clay dishes were mounted one atop another.
Present-day luminaires (a complete lighting unit is properly referred to as a luminaire) consist of lighting fixtures and one or more light sources. The accessories distribute the light flux in the surrounding space and protect the eyes from being blinded by the light source. In addition, the lighting fixtures permit changes in such characteristics of the light flux as intensity and spectral composition. Other purposes of the lighting fixtures include the mounting of the light source, the connection of the light source to the supply system, and the protection of the light source from mechanical damage and from the effects of the surroundings. The most important part of the lighting fixtures is the optical system, which consists of the optical components that effect the distribution and conversion of the light flux. Such components include reflectors, refractors, diffusers, filters, protective glass, and screening gratings or rings. Luminaires with gas-discharge light sources may include devices for starting the lamp and for stabilizing its operation.
Luminaires must satisfy a number of engineering, technical, economic, aesthetic, installation, and operating requirements, and they must be safe and reliable. The principal criteria for evaluating the operation of a luminaire are the character of the light distribution, the magnitudes of the cutoff angles (the angles determining the zone in which the observer’s eye is protected from the direct action of the light source), the luminance of the luminaire surfaces within the field of vision, and the efficiency of the luminaire.
Luminaires can be classified according to their functional purpose into luminaires for general lighting and luminaires for local lighting. Those for general lighting are used to produce the required illuminance of the working surface of a room and to provide a favorable distribution of brightness. Those for local lighting are designed primarily to provide increased illuminance of individual areas of the working surface. When a classification is made according to the method of mounting, the following types can be distinguished: suspended, ceiling, built-in, built-on, wall, table, floor, crown, overhanging, hand, and head luminaires or lamps. With respect to the degree of protection from dust and moisture, the following types are distinguished: open, covered, completely or partially dustproof, unprotected from water, drop-proof, rain-proof, spray-proof, splash-proof, watertight, and airtight. Special explosion-proof luminaires are also available.
Many types of luminaires are mass-produced. The annual output of the USSR is several tens of millions of units. Custom-built luminaires of great artistic value are also made. Examples are the chandeliers of the Moscow Kremlin, the Hermitage, and the Bolshoi Theater of the USSR.
REFERENCESAizenberg, Iu. B., and V. F. Efimkina. Osvetitel’nye pribory s luminestsentnymi lampami. Moscow, 1968.
Trembach, V. V. Svetovye pribory. Moscow, 1972.
IU. B. AIZENBERG
rear light, lamp
LAMP(Linux, Apache, MySQL, PHP) The common set of system software and programming languages used in a Linux-based Web server. LAMP comprises the Linux operating system, Apache Web server software and MySQL database management system (DBMS). Applications are programmed in PHP, but also in the Perl and Python languages. A LAMP application is a non-Windows environment; however, there is a Windows equivalent: WAMP is Windows, Apache, MySQL and PHP.
MAMP and xAMP
In the Mac world, the Mac operating system replaces Linux, resulting in MAMP: Mac, Apache, MySQL, PHP. The acronym xAMP refers to any and all operating systems used with AMP software: X=cross platform, Apache, MySQL and PHP. See Linux, Apache, MySQL, PHP, Perl, Python and MEAN.