Britannica Concise 2005

menopause Final cessation of menstruation, ending female fertility. It usually begins between ages 45 and 55. A gradual decline in function of the ovaries reduces estrogen production. Ovulation becomes irregular and gradually ceases. The length of the menstrual cycle and periods may vary; flow may lessen or increase. Adjustment of the endocrine system to estro¬ gen reduction causes hot flashes, often at night, with a warm sensation, flushing, and sweating; other symptoms, such as irritability and head¬ aches, may be related more to reactions to aging. Removal or destruction of the ovaries to treat disease causes artificial menopause, with similar but more sudden effects. Changes in hormone balance usually cause no physical or mental disturbances. However, the protective effect of estro¬ gen against osteoporosis and atherosclerosis is lost, and risks of fracture and coronary heart disease increase.

menorah \m3-'nor-3\ Multibranched candelabra used by Jews during the festival of Hanukkah. It holds nine candles (or has nine receptacles for oil). Eight of the candles stand for the eight days of Hanukkah—one is lit the first day, two the second, and so on. The ninth candle, or sham- mash (“servant”) light—usually set in the centre and raised above the others—is used to light the others.

The menorah is an imitation of the seven-branched golden candelabra of the Tabernacle, which signified the seven days of creation. The menorah is also an ancient symbol of Jewish identity and the official symbol of the modern state of Israel.

Menotti Vms-'na-teV Gian Carlo

(b. July 7, 1911, Cadegliano, Italy)

Italian-born U.S. composer, libret¬ tist, and stage director. Having writ¬ ten an opera by age 10, he spent his early teens absorbing the repertoire at La Scala. Arturo Toscanini recom¬ mended study at the Curtis Institute; there he met Samuel Barber, who would become his lifelong companion. In 1939 he produced the radio opera The Old Maid and the Thief, The Island God (1942) was an unsuc-

Menno Simons, engraving by Christo¬ pher van Sichem, 1605-08.

COURTESY OF THE MENNONITE LIBRARY AND ARCHIVES, NORTH NEWTON, KANSAS

Roman soldiers carrying the menorah from the Temple of Jerusalem, ad 70; detail of a relief on the Arch of Titus, Rome, ad 81.

AUNARI/ART RESOURCE, NEW YORK

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Menshevik ► mercantile agency I 1237

cessful commission for the Metropolitan Opera. The Medium (1946) had a Broadway run, and The Consul (1950, Pulitzer Prize) was also success¬ ful. The highly popular Amahl and the Night Visitors (1951), for televi¬ sion, was followed by The Saint ofBleecker Street (1955, Pulitzer Prize). In 1958 he founded the Festival of Two Worlds in Spoleto, Italy; it enjoyed great success, and in 1977 he founded a New World counterpart in Charleston, S.C.

Menshevik Vmen-sho-vikA Member of the non-Leninist wing of the Russian Social-Democratic Workers' Party. The group evolved in 1903 when L. Martov called for a mass party modeled after western European groups, as opposed to Vladimir Iuch Lenin’s plan to restrict the party to pro¬ fessional revolutionaries. When Lenin’s followers obtained a majority on the party central committee, they called themselves Bolsheviks (“those of the majority”), and Martov and his group became the Mensheviks (“those of the minority”). The Mensheviks played active roles in the Russian Revolution of 1905 and in the St. Petersburg soviet, but they became divided over World War I and later by the Russian Revolution of 1917. They attempted to form a legal opposition party but in 1922 were perma¬ nently suppressed.

Menshikov Ymyen-shi-kdfX, Aleksandr (Danilovich) (b. Nov. 16, 1673, Moscow, Russia—d. Nov. 23, 1729, Berezov, Siberia, Russian Empire) Russian soldier and administrator. In 1686 he became an orderly for Peter I and soon was the tsar’s favourite. Menshikov led troops to vic¬ tories in the Second Northern War, including the Battle of Poltava, after which he received the title of field marshal (1709). As an administrator from 1714, he was criticized for corrupt practices as he amassed power and wealth. After Peter’s death in 1725, Menshikov succeeded in having his ally Catherine I proclaimed empress, making him the virtual ruler of Russia. After her death in 1727, he arranged to have his daughter marry the young Tsar Peter II, but his enemies turned Peter against him and forced Menshikov’s exile to Siberia.

menstruation Periodic discharge from the vagina of blood, secretions, and shed mucous lining of the uterus (endometrium). The endometrium prepares to receive a fertilized egg by thickening and producing secre¬ tions. If the egg released by the ovary is not fertilized, the endometrium breaks down and is expelled by contractions of the uterus. The first men¬ struation (menarche) occurs after other changes of puberty, usually at 11-13 years of age, apparently triggered by the passing of a weight thresh¬ old. Bleeding may be irregular or heavy at first. In adult women, men¬ strual periods begin at an average interval of 28 days and last about five days; some variation among women and in the same woman is normal. Uterine contractions are felt as cramps. The amount of blood lost is usu¬ ally less than 1.7 oz (50 ml). Menstruation ends with menopause. Men¬ strual disorders include dysmenorrhea (painful menstruation) and amenorrhea (no bleeding), heavy or light bleeding, and uterine bleeding. See also PREMENSTRUAL SYNDROME.

mental disorder Any illness with a psychological origin, manifested either in symptoms of emotional distress or in abnormal behaviour. Most mental disorders can be broadly classified as either psychoses or neuro¬ ses (see neurosis; psychosis). Psychoses (e.g., schizophrenia and bipolar dis¬ order) are major mental illnesses characterized by severe symptoms such as delusions, hallucinations, and an inability to evaluate reality in an objec¬ tive manner. Neuroses are less severe and more treatable illnesses, includ¬ ing DEPRESSION, ANXIETY, and PARANOIA as well as OBSESSIVE-COMPULSIVE DISORDERS

and post-traumatic stress disorders. Some mental disorders, such as Alzhe¬ imer disease, are clearly caused by organic disease of the brain, but the causes of most others are either unknown or not yet verified. Schizophre¬ nia appears to be partly caused by inherited genetic factors. Some mood disorders, such as mania and depression, may be caused by imbalances of certain neurotransmitters in the brain; they are treatable by drugs that act to correct these imbalances (see psychopharmacology). Neuroses often appear to be caused by psychological factors such as emotional depriva¬ tion, frustration, or abuse during childhood, and they may be treated through psychotherapy. Certain neuroses, particularly the anxiety disorders known as phobias, may represent maladaptive responses built up into the human equivalent of conditioned reflexes.

mental hygiene Science of maintaining mental health and preventing disorders to help people function at their full mental potential. It includes all measures taken to promote and preserve mental health: rehabilitation of the mentally disturbed, prevention of mental illness, and aid in coping in a stressful world. Community mental health acknowledges the relation

between mental health, population pressures, and social unrest. It also deals with social problems, from drug addiction to suicide prevention. Treatment of the mentally ill through the ages has ranged from neglect, ill treatment, and isolation to active treatment and integration into the community, often in response to crusading reformers. Prevention of men¬ tal illness includes prenatal care, child-abuse awareness programs, and counseling for crime victims. Treatment includes psychotherapy, drug therapy, and support groups. One of the most important efforts is public education to combat the stigma still attached to mental illness and encour¬ age those affected to seek treatment.

mental retardation Subaverage intellectual ability that is present from birth or infancy and is manifested by abnormal development, learn¬ ing difficulties, and problems in social adjustment. A standardized intel¬ ligence test is a common method of identification. Individuals with IQ scores of 53-70 are usually classified as mildly retarded and are able to learn academic and pre-vocational skills with some special education. Those with scores of 36-52 are classified as moderately retarded and are able to learn functional academic skills and undertake semiskilled work under supervised conditions. Those in the severe (21-35) and profound (below 21) ranges require progressively more supervision or full-time custodial care. Mental retardation can be caused by genetic disorders (such as Down's syndrome), infectious diseases (such as meningitis), meta¬ bolic disorders, poisoning from lead, radiation, or other toxic agents, inju¬ ries to the head, and malnutrition.

menthol Crystalline organic compound of the isoprenoid family. It has a strong, minty, cooling odour and taste. It is obtained from the oil of the Japanese mint or made synthetically and is used in cigarettes, cosmetics, chest rubs, cough drops, toothpastes, and flavourings. Of its two optical isomers (see optical activity; isomerism), only 1-menthol has the desirable cooling effect.

Menuhin Vmen-yo-wonX, Yehudi, Lord Menuhin of Stoke d'Abernon (b. April 22, 1916, New York, N.Y., U.S.—d. March 12, 1999, Berlin, Ger.) U.S.-born British violinist and conductor. Raised in San Francisco, he made his debut at age seven. In 1927 he studied with George Enescu (1881-1955) in Paris; he returned to perform to tremen¬ dous acclaim in New York the same year and went on to astound audi¬ ences worldwide with his precocious depth and proficiency. From 1959 he lived in London, but he did not become a British citizen until 1985. He directed the Bath Festival (1958-68) and the Gstaad Festival from 1956. In 1958 he founded his own chamber orchestra. Often accompa¬ nied by his pianist sister, Hephzibah (1920-81), he also made recordings with the sitarist Ravi Shankar.

Menzies Vmen- I zez\, Sir Robert (Gordon) (b. Dec. 20, 1894, Jeparit, Victoria. Austl.—d. May 16, 1978, Melbourne) Australian states¬ man and prime minister (1939-41, 1949-66). A successful lawyer, he served as Australia’s attorney general (1934-39). Leader of the United Australia Party, he served as prime minister (1939—41). He organized the Liberal Party in 1944 and again became premier in 1949. In the 1950s he fostered industrial growth in Australia and immigration from Europe. He strengthened military ties with the U.S. and encouraged the ANZUS Pact and Australia’s membership in the Southeast Asia Treaty Organization. He retired in 1966 after the longest ministry in Australian history.

mer \'mer\ Among the Cheremi and Udmurt peoples of Russia, a sacred grove where people of several villages gathered periodically to hold reli¬ gious festivals and sacrifice animals to nature gods. The groves where the mer festivals were held were not fenced (see lud) and did not have per¬ manent altars. Mer festivals were infrequent; five years or more might elapse between them.

mercantile agency Specialized organization that supplies informa¬ tion on the creditworthiness and financial strength of business firms. The first such agency, the Mercantile Agency, was founded in New York City in 1841. It provided information to businesses that were expanding nation¬ ally and were unable to assess the credit history of prospective custom¬ ers in distant locations. It changed its name to R. G. Dun & Co. after 1859 and merged with the Bradstreet Co. in 1933 to form Dun & Brad- street, Inc., the best-known mercantile agency. Mercantile agencies may provide information on all types of business firms or may limit their investigations to firms in a particular line of trade or a particular region. Most agencies provide both general and special reports. General reports, issued periodically on all firms investigated by the agency, assign a rat-

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© 2006 Encyclopaedia Britannica, Inc.

1238 I mercantile law ► Mercury

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ing to the firm’s financial statement and creditworthiness. Special reports containing more detailed information are issued to clients of the agency on request. See also credit bureau.

mercantile law See business law

mercantilism Economic theory and policy influential in Europe from the 16th to the 18th century that called for government regulation of a nation’s economy in order to increase its power at the expense of rival nations. Though the theory existed earlier, the term was not coined until the 18th century; it was given currency by Adam Smith in his Wealth of Nations (1776). Mercantilism’s emphasis on the importance of gold and silver holdings as a sign of a nation’s wealth and power led to policies designed to obtain precious metals through trade by ensuring “favourable” trade balances (see balance of trade), meaning an excess of exports over imports, especially if a nation did not possess mines or have access to them. In a favourable trade balance, payments for the goods or services had to be made with gold or silver. Colonial possessions were to serve as markets for exports and as suppliers of raw materials to the mother coun¬ try, a policy that created conflict between the European colonial powers and their colonies, in particular fanning resentment of Britain in the North American colonies and helping bring about the American Revolution. Mercantilism favoured a large population to supply labourers, purchasers of goods, and soldiers. Thrift and saving were emphasized as virtues because they made possible the creation of capital. Mercantilism provided a favourable climate for the early development of capitalism but was later severely criticized, especially by advocates of laissez-faire, who argued that all trade was beneficial and that strict government controls were counter¬ productive.

Mercator Vmsr-'ka-toA, Gerardus orig. Gerard Kremer (b.

March 5, 1512, Rupelmonde, Flanders—d. Dec. 2, 1594, Duisburg, Duchy of Cleve) Flemish cartographer. He received a master’s degree in 1532 from the University of Louvain (Belgium), where he settled. By 24 he was a skilled engraver, calligrapher, and scientific-instrument maker. He and his colleagues made Louvain a centre for construction of maps, globes (terrestrial and celestial), and astronomical instruments. He was appointed court cosmographer to Duke Wilhelm of Cleve in 1564, and in 1569 he perfected what has become known as the Mercator projection, in which parallels and meridians are rendered as straight lines spaced so as to produce at any point an accurate ratio of latitude to longitude. It permitted mariners to steer a course over long distances, plotting straight lines without continually adjusting compass readings. While the merid¬ ians are equally spaced parallel vertical lines, the lines of latitude are spaced farther and farther apart as their distance from the Equator increases; on world maps the projection greatly enlarges areas distant from the Equator.

mercenary Vmor-s^-.er-eV Hired professional soldier who fights for any state or nation without regard to political principles. From the earli¬ est days of organized warfare, governments supplemented their military forces with mercenaries. After the Hundred Years’ War (1337-1453), Swiss soldiers were hired out all over Europe by their own cantonal gov¬ ernments and won a high reputation. Rulers of the German state of Hesse also hired out their soldiers, and Hessian troops fought for the British in the American Revolution. Since the late 18th century, most mercenaries have been individual soldiers of fortune.

Mercer, Johnny orig. John Herndon Mercer (b. Nov. 18, 1909, Savannah, Ga., U.S.—d. June 25, 1976, Bel Air, Calif.) U.S. songwriter. After moving to New York City in the late 1920s, Mercer began to write lyrics while supporting himself as an actor. He later joined Paul White- man’s orchestra as singer and master of ceremonies. In 1939 he joined Benny Goodman’s Camel Caravan radio show. In 1942 Mercer cofounded Capitol Records. On Broadway, he collaborated with Harold Arlen on St. Louis Woman (1946) and Saratoga (1959) and also provided lyrics for Seven Brides for Seven Brothers (1954), Li’l Abner (1956), and Foxy (1964). His songs for films won four Academy Awards. He collaborated with composers such as Hoagy Carmichael, Henry Mancini, Jerome Kern, and Jimmy Van Heusen and is credited with more than 1,000 lyrics, includ¬ ing those for “Ac-cent-tchu-ate the Positive,” “One for My Baby,” “Autumn Leaves,” and “Moon River.”

mercerization X.mor-ss-ro-'za-shonX Chemical treatment applied to cotton fibres or fabrics to make them permanently able to accept dyes and various chemical finishes more easily. The method, patented in 1850 by the English calico printer John Mercer, also gives cotton cloth

increased tensile strength and greater absorptive properties. Higher-quality cotton goods are usually mercerized. The treatment consists of dipping the yam or fibre in a solution of sodium hydroxide and then treating the material with water or acid to neutralize the sodium hydroxide.

merchandising Element of marketing concerned especially with the sale of goods and services to customers. One aspect of merchandising is advertising, which aims to capture the interest of the segment of the popu¬ lation most likely to buy the product. Merchandising also involves prod¬ uct display; companies provide retailers with display and promotional materials and negotiate shelf space for their products. The development of sales strategies includes the determination of pricing, discounts, and special offers; the invention of sales pitches; and the identification of avenues for sales, including store-based retailing and alternative means such as direct-mail marketing, telemarketing, commercial Web sites, vend¬ ing machines, and door-to-door sales.

Merchant, Ismail See James Ivory

merchant marine Commercial ships of a nation, whether privately or publicly owned, and the personnel who operate such ships, as distinct from the personnel of naval vessels. Merchant ships are used to transport people, raw materials, and manufactured goods. Merchant fleets can be important economic assets for nations with limited natural resources or a small industrial base. By carrying the commerce of other nations on the seas, a merchant fleet contributes to its home nation’s foreign-exchange earnings, promotes trade, and provides employment. The U.S. Merchant Marine Academy (founded 1943) is in Kings Point, N.Y.

Mercia Vmsr-shoN Ancient kingdom, central England. One of the Anglo- Saxon kingdoms of the Heptarchy, it comprised the border areas, corre¬ sponding to modern Staffordshire, Derbyshire, Nottinghamshire, and northern West Midlands and Warwickshire. Offa, who ruled from 757 to 796, created a single state from the River Humber to the English Chan¬ nel. After Offa’s death, Mercia declined, overshadowed by Wessex. In 877 the Danes divided Mercia into English and Danish sections. After the reconquest of the Danish lands in the early 10th century, it came under the rule of Wessex.

Mercury In Roman religion, the god of merchants, commonly identified with the Greek messenger of the gods, Hermes. His temple on Rome’s Aventine Hill was dedicated in 495 bc. The goddess Maia was identified as his mother, and the two were honoured in a festival on May 15. Mer¬ cury is sometimes depicted holding a purse, symbolic of his business functions. More often he is given the attributes of Hermes and portrayed wearing winged sandals or a winged cap and carrying a caduceus.

mercury or quicksilver Metallic chemical element, chemical symbol Hg, atomic number 80. Mercury is the only elemental metal that is liquid at ordinary temperatures, with a freezing point of -38 °F (-39 °C) and a boiling point of 674 °F (356.9 °C). Silvery white, dense, toxic (see mer¬ cury poisoning), and a good conductor of electricity, mercury is occasion¬ ally found free in nature but usually occurs as the red sulfide ore, cinnabar (HgS). It has many uses—in dental and industrial amalgams, as a catalyst, in electrical and measuring apparatus and instruments (e.g., thermom¬ eters), as the cathode in electrolytic cells, in mercury-vapour lamps, and as a coolant and neutron absorber in nuclear power plants. Many of mer¬ cury’s compounds, in which it has valence 1 or 2, are pigments, pesti¬ cides, and medicinals. It is a dangerous pollutant because it concentrates in animal tissues in increasing amounts up the food chain.

Mercury Innermost planet of the solar system. Its average distance from the Sun is about 36 million mi (58 million km), but its highly elliptical orbit carries it 7.5 million mi (12 million km) nearer to and farther from the Sun. It is the second-smallest major planet (after Pluto), having a diameter of about 3,030 mi (4,880 km) and a mass about one-eighteenth of Earth’s. With the shortest period of revolution (only 88 Earth days) and the highest average orbital speed (30 mi/second, or 48 km/second) of any planet, it is aptly named after the fleet-footed Roman messenger god. It spins very slowly, making one complete rotation relative to the stars every 59 Earth days, while its solar day (from one sunrise to the next) is 176 Earth days, owing to its revolution around the Sun. Its surface is heavily cratered. Its most impressive feature is perhaps the 800-mi (1,300- km) Caloris Basin, formed by a huge meteorite impact. Mercury also has steep cliffs that extend for hundreds of miles. The discovery of a mag¬ netic field in its vicinity suggests it has a large iron core, which would account for a mean density almost as high as Earth’s. Its atmosphere is

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Mercury ► Merimee I 1239

negligible; its surface gravity, about one-third that of Earth’s, holds an exceedingly tenuous layer of gases. Temperatures at its surface change dramatically, ranging from a high that can exceed 800 °F (425 °C) on the sunward side to a low of about -290 °F (-180 °C) at the end of its night.

Mercury First series of U.S. manned spaceflights (1961-63), which began about three weeks after Yury A. Gagarin became the first human in space. In May 1961 Alan B. Shepard rode the first Mercury space cap¬ sule, Freedom 7, on a 15-minute, 302-mi (486-km) suborbital flight, attaining a maximum altitude of 116 mi (186 km). The first U.S. manned flight in orbit was that of the Friendship 7, carrying John H. Glenn, Jr., in February 1962; it completed three orbits. The last Mercury flight, Faith 7, launched in May 1963, was the longest, making 22 orbits in about 34 hours.

mercury poisoning Harmful effects of mercury compounds. Manu¬ facture of paints, various household items, and pesticides uses mercury; the finished product and the waste products released into air and water may contain mercury. The aquatic food chain can concentrate organic mercury compounds in fish and seafood, which, if eaten by humans, can affect the central nervous system, impairing muscle, vision, and cerebral function, leading to paralysis and sometimes death (see Minamata disease). Acute mercury poisoning causes severe digestive-tract inflammation. Mercury accumulates in the kidneys, causing uremia and death. Chronic poisoning, from occupational inhalation or skin absorption, causes metal¬ lic taste, oral inflammation, blue gum line, extremity pain and tremor, weight loss, and mental changes (depression and withdrawal). Drugs con¬ taining mercury can cause sensitivity reactions, sometimes fatal. In young children, acrodynia (pink disease) is probably caused by an organic mer¬ cury compound in house paints.

Meredith, George (b. Feb. 1 Eng.—d. May 18, 1909, Box Hill, Surrey) English novelist and poet. Though ostensibly launched on a law career at age 18, he concentrated instead on writing poems and articles and making translations. Because they brought in little money, he turned to writing prose. The novel The Ordeal of Richard Feverel (1859) is typical of his best work, rich in allusion, metaphor, lyrical prose, witty dialogue, and psycho¬ logical insight. It failed to make him wealthy, and he was forced to begin reading manuscripts for a publisher. Writing in his spare time, he pro¬ duced a comedy, Evan Harrington (1860), and a volume of poems, Modern Love (1862). He finally won critical and popular acclaim with the novels The Egoist (1879) and Diana of the Crossways (1885). His works are noted for their use of interior monologue and their treatment of w<

!, 1828, Portsmouth, Hampshire,

George Meredith, detail of an oil painting by G.F. Watts, 1893; in the National Portrait Gallery, London.

COURTESY OF THE NATIONAL PORTRAIT GALLERY, LONDON