machine Device that amplifies or replaces human or animal effort to accomplish a physical task. A machine may be further defined as a device consisting of two or more parts that transmit or modify force and motion in order to do work. The five simple machines are the lever, the wedge, the wheel and axle, the pulley, and the screw; all complex machines are com¬ binations of these basic devices. The operation of a machine may involve the transformation of chemical, thermal, electrical, or nuclear energy into mechanical energy, or vice versa. All machines have an input, an output, and a transforming or modifying and transmitting device. Machines that receive their input energy from a natural source (such as air currents, mov¬ ing water, coal, petroleum, or uranium) and transform it into mechanical energy are known as prime movers; examples include windmills, water¬ wheels, TURBINES, STEAM ENGINES, and INTERNAL-COMBUSTION ENGINES.
machine gun Automatic weapon capable of rapid, sustained fire, usu¬ ally 500-1,000 rounds per minute. Developed in the late 19th century by such inventors as Hiram Maxim, it profoundly altered modem warfare. The World War I battlefield was dominated by the belt-fed machine gun, which remained little changed into World War II. Modem machine guns are clas¬ sified into three groups: the squad automatic weapon, chambered for small- calibre assault-rifle ammunition and operated by one soldier; the general- purpose machine gun, firing full-power rifle ammunition and operated by two; and the heavy machine gun, firing rounds of 12.7 mm (.5 in) or higher and often mounted on an armoured vehicle. See also submachine gun.
machine language or machine code Elemental language of com¬ puters, consisting of a string of 0s and Is. Because machine language is the lowest-level computer language and the only language that comput¬ ers directly understand, a program written in a more sophisticated lan¬ guage (e.g., C, Pascal) must be converted to machine language prior to execution. This is done via a compiler or assembler. The resulting binary file (also called an executable file) can then be executed by the CPU. See also ASSEMBLY LANGUAGE.
Guillaume de Machaut, detail of a min¬ iature from Oeuvres de Guillaume de Machaut, c. 1370-80; in the Biblio- theque Nationale (Ms. Fr. 1584).
COURTESY OF THE BIBUOTHEQUE NATIONALE, PARIS
Niccolo Machiavelli, detail of an oil painting by Santi di Tito; in the Palazzo Vecchio, Florence.
AUNARI/ART RESOURCE, NEW YORK
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1160 I machine tool ► mackerel shark
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machine tool Stationary, power-driven machine used to cut, shape, or form materials such as metal and wood. Machine tools date from the invention of the steam engine in the 18th century; most common machine tools were designed by the middle of the 19th century. Today dozens of different machine tools are used in the workshops of home and industry. They are frequently classified into seven types: turning machines such as lathes; shapers and planers; power drills or drill presses; milling machines; grinding machines; power saws; and presses (e.g., punch presses).
machismo \ma-'chez-mo\ Exaggerated pride in masculinity, perceived as power, often coupled with a minimal sense of responsibility and dis¬ regard of consequences. In machismo there is supreme valuation of char¬ acteristics culturally associated with the masculine and a denigration of characteristics associated with the feminine. It has for centuries been a strong current in Latin American politics and society. Caudillos (military dictators), prominent in the history of Latin America, have typified machismo with their bold and authoritarian approach to government and their willingness to employ violence to achieve their ends.
Mach's principle Vmaks\ Hypothesis that the inertial forces acting on a body in accelerated motion are determined by the quantity and distri¬ bution of matter in the universe. Albert Einstein found its suggested con¬ nection between geometry and matter helpful in formulating his theory of general relativity; unaware that George Berkeley had proposed similar views in the 18th century, he attributed the idea to Ernst Mach. He abandoned the principle when he realized that inertia is assumed in the geodesic equation of motion (see geodesy) and need not depend on the existence of matter elsewhere in the universe.
Machu Picchu \‘ma-chu- , pek-chu\ Ancient fortress city of the Incas in the Andes Mountains, south-central Peru. Perched near Cuzco in a narrow saddle between two sharp peaks, at an elevation of 7,710 ft (2,350 m), it escaped detection by the Spaniards, and its existence was made known only in 1911 by U.S. explorer Hiram Bingham. One of the few pre- Columbian urban centres found nearly intact, it is about 5 sq mi (13 sq km) in area and includes a temple and a citadel. The period of occupancy is uncertain. Made a UNESCO World Heritage site in 1983, it is a popular tourist attraction.
Maclver Vmo-'ke-vorV Robert M(orrison) (b. April 17, 1882,
Stornoway, Outer Hebrides,
Scot.—d. June 15, 1970, New York,
N.Y., U.S.) Scottish-born U.S. soci¬ ologist and political scientist. He taught at the University of Aberdeen and later at Canadian and U.S. uni¬ versities, principally Columbia (1915-26). He believed in the compatibility of individualism and social organization and saw societies as evolving from highly communal states to states in which individual functions and group affiliations were extremely specialized. His works included The Modern State (1926), Leviathan and the People (1939), and The Web of Government (1947).
Mack, Connie orig. Cornelius (Alexander) McGillicuddy (b.
Dec. 22/23, 1862, East Brookfield, Mass., U.S.—d. Feb. 8, 1956, Phila¬ delphia, Pa.) U.S. baseball manager and team executive. Mack played professional baseball (1886-96), usually as a catcher, before becoming manager of the Milwaukee Brewers (1897-1900) and the Philadelphia Athletics (1901-50). He was president of the Athletics from 1937 to 1953. His teams won 3,776 games and lost 4,025, both all-time records. He helped establish the American League.
Mackenzie \mo-'ken-ze\, Alexander (b. Jan. 28, 1822, Logierait, Perth, Scot.—d. April 17, 1892, Toronto, Ont., Can.) Scottish-born Cana¬ dian politician, first Liberal prime minister of Canada (1873-78). He emi¬ grated to Canada West (now Ontario) in 1842. In 1852 he became editor of a local Liberal newspaper and befriended George Brown, leader of the Reform Party. When the Dominion of Canada was created in 1867, Mack¬ enzie was elected to the House of Commons, where he led the Liberal
opposition. As prime minister, his efforts at renewed reciprocity with the U.S. failed to address economic concerns, and his government was defeated in 1878. He resigned as leader of the opposition but held a seat in Parliament until his death.
Mackenzie, Sir Alexander (b. 17557, Stornoway, Lewis and Har¬ ris, Outer Hebrides, Scot.—d. March 11, 1820, near Pitlochry, Perth) Scottish-born Canadian explorer. Immigrating to Canada as a young man, he entered a fur-trading firm in 1779. In 1788 he set up a trading post, Fort Chipewyan, on Lake Athabasca. From there he began an expedition (1789) that followed the Mackenzie River from Great Slave Lake to the Arctic Ocean. In 1793 he journeyed from Fort Chipewyan through the Rocky Mountains to the Pacific coast, thereby becoming the first Euro¬ pean to complete a transcontinental crossing north of Mexico.
Mackenzie, Sir (Edward Montague) Compton (b. Jan. 17, 1883, West Hartlepool, Durham, Eng.—d. Nov. 30, 1972, Edinburgh, Scot.) British novelist and playwright. Educated at Oxford University, he gave up legal studies to finish his first play, The Gentleman in Grey (1906). During World War I he directed the Aegean Intelligence Service in Syria; when he wrote about those experiences in Greek Memories (1932), he was prosecuted under Britain’s Official Secrets Act. He founded Gramo¬ phone magazine in 1923 and edited it until 1962. He served as rector of Glasgow University (1931-34) and as literary critic for the London Daily Mail ; his more than 100 novels, plays, and biographies include 10 vol¬ umes of memoirs.