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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
as equals of men.
Meredith, James (Howard) (b. June 25, 1933, Kosciusko, Miss., U.S.) U.S. civil rights leader. He grew up in poverty in Mississippi, the most racially segregated state in the U.S. In 1961 he applied for admis¬ sion to the all-white University of Mississippi. He won a legal battle to be admitted, but federal troops and Justice Department officials had to be brought in to enforce the court order. While participating in a voter- registration drive after his graduation from “Ole Miss,” he was shot and wounded by a white supremacist.
merengue \mo-'req-ga\ Couple dance from the Dominican Republic or Haiti, danced throughout Latin America. Originally a folk dance, it has become a ballroom dance, where it is danced with a limping step, the weight always on the same foot. Varieties include the jaleo and juango- mero. Dominican merengue music became widely popular in the late 20th century.
mereology \,mir-e-'a-l3-je\ Branch of logic, founded by Stanislaw Lesniewski, that studies class expressions and the relations between parts and wholes. It rejects the hierarchy of sets generated in set theory through the member-of relation and instead proposes a part-whole relationship. It
has attracted philosophers of logic and mathematics who are nominalists (see universal), those who suspect set theory of being inherently Platonis- tic, and those who are otherwise suspicious of the complex entities pro¬ posed by, and the complicated assumptions needed for, set theory.
merganser or fish duck Any species of the diving duck genus Mer- gus. Essentially freshwater birds, they are classified as a sea duck (tribe Mergini). Mergansers have a long body and a narrow, serrated, hooked bill for catching fish. The males of all but the common merganser, or goosander (M. merganser), are crested. The common merganser, the hooded merganser (M cucullatus), the red-breasted merganser (M. ser- rator ), and the smew (M. albellus), a small, compact merganser with a short bill, live in northern regions; the only southern species is the Bra¬ zilian merganser (M. octosetaceus ). Mergansers are called trash ducks because their flesh is rank. See also shelduck.
Mergenthaler Vmor-gon-.tha-brV Ottmar (b. May 11, 1854, Hach- tel, Wtirttemberg—d. Oct. 28, 1899, Baltimore, Md., U.S.) German-U.S. inventor. He immigrated to the U.S. in 1872. While working in a Balti¬ more machine shop he began experimenting with type molds, and in 1884 he patented the Linotype typesetting machine. The reduced costs achieved by thus speeding up the typesetting process led to a dramatic expansion of all kinds of publishing.
merger Combination of two or more independent business corporations into a single enterprise, usually involving the absorption of one or more firms by a dominant firm. The dominant firm may purchase the other firm’s assets with cash or securities, purchase the other firm’s stock, or issue its own stock to the other firm’s stockholders in exchange for their shares in the acquired firm (thus acquiring the other company’s assets and liabilities). In horizontal mergers, both firms produce the same commod¬ ity or service for the same market. In vertical mergers, a firm acquires either a supplier or a customer. If the merged business is not related to that of the acquiring firm, the new corporation is called a conglomerate. The reasons for mergers are various: the acquiring firm may seek to eliminate a competitor, to increase its efficiency, to diversify its products, services, and markets, or to reduce its taxes.
Mergui Archipelago \m3r-'gwe\ Group of more than 200 islands in the Andaman Sea off the coast of southeastern Myanmar. The largest island is Mali Kyun (Tavoy Island) at its northern end. Other major islands in the group include Kadan (King), Thayawthadangyi (Elphinstone), Daung (Ross), Saganthit (Sellore), Bentinck, Letsok-aw (Domel), Kan- maw (Kisseraing), Lanbi (Sullivan’s), and Zadetkyi (St. Matthew’s). Mountainous and jungle-covered, the islands are inhabited chiefly by the Selungs.
Merida City (pop., 2000: 660,884), capital of YucatAn state, southeast¬ ern Mexico. It lies near the northwestern tip of the Yucatan Peninsula, south of Progreso; its port is on the Gulf of Mexico. It was founded in 1542 on the site of the ancient Maya city of T’ho. It has numerous colo¬ nial buildings and a 16th-century cathedral. Yucatan University and the Regional Technical Institute of Merida are located there. It serves as a tourist base for trips to nearby Maya cities, including Chichen ItzA, Dzi- bilchaltun, Uxmal, and Kabah.
Merida Vma-re-tha\ ancient Emerita Augusta Town (pop., 2001: 50,271), capital of the autonomous community of Extremadura, western Spain. Situated on the northern bank of the Guadiana River, it was founded by the Romans in 25 bc. It served as the capital of the province of Lusitania and became one of the most important towns in Iberia. Occu¬ pied in ad 713 by the Moors, it was recaptured in 1228 by Alfonso IX of Leon, who granted it to the Knights of Santiago. It is known for its Roman ruins, including a bridge, an amphitheatre, and an aqueduct. The modern town’s economy is based on agricultural trade and tourism.