ormolu Vor-mo-.liA (from French dorure d’or moulu, “gilding with gold paste”) Gold-coloured alloy made up of copper, zinc, and sometimes tin in various proportions but usually at least 50% copper. It is used in mounts (ornaments on borders, edges, and as angle guards) for furniture and for other decorative purposes. After the molten alloy has been poured into a mold and allowed to cool, it is gilded with powdered gold mixed with mercury. It is then fired at a temperature that evaporates the mercury, leaving a gold surface. Ormolu was first produced in France in the mid- nth century, and France remained its main centre of production. See photograph opposite.
Ormonde, James Butler, 12th earl and 1st duke of (b. Oct. 19, 1610, London, Eng.—d. July 21, 1688, Kingston Lacy, Dorset) Anglo- Irish statesman. Born into the prominent Butler family of Ireland, he suc¬ ceeded to the earldom of Ormonde in 1632. In service to the English crown in Ireland from 1633, he fought against the Catholic rebellion from 1641. He concluded a peace with the Catholic confederacy in 1649, then rallied support for Charles II, but he was forced to flee when Oliver Crom¬ well landed at Dublin. He was Charles’s adviser in exile (1650-60). After the Restoration he was appointed lord lieutenant of Ireland (1662-69, 1677-84), where he encouraged Irish commerce and industry. He was created a duke in 1682.
Ormuz See Hormuz
ornamentation In music, the addition of notes for expressive and aesthetic purposes. For example, a long note may be ornamented by rep¬ etition or by alternation with a neighboring note (“trill”); a skip to a non- adjacent note can be filled in with the intervening notes; or the resolution of a dissonance (see consonance and dissonance), because of its inevita¬ bility, can be delayed.
ornamentation In architecture, applied embellishment in various styles that is a distinguishing characteristic of buildings, furniture, and household items. Ornamentation often occurs on entablatures, columns, the tops of buildings, and around entryways and windows, especially in the form of moldings. Throughout antiquity and into the Renaissance, and later for religious buildings, applied ornament was very important, often having symbolic meaning. The anthemion petal motif was especially popular on the moldings of ancient Greek cornices. Other motifs from antiquity include the Egyptian cartouche (oval), fretwork (banding) of capitals, fluting and reeding of columns, bas-relief egg-and-dart moldings (with alternating oval and pointed forms), and scrollwork such as that found on Ionic capitals and in the running-dog pattern (or wave scroll). Brattishing refers to the continuous embellishment around the top of a wall, common in the Gothic period. The diaper motif, an allover pattern of small repeated shapes, was also often used in this period. The use of strapwork (interlaced scrollwork), which originated with Islamic metal¬ work, is characteristic of Mannerist architecture and furniture.
Orne V6m\ River River, northwestern France. It is 94 mi (152 km) long and flows through the Orne and Calvados departments past Caen into the English Channel. Its bridges were seized by the Allied forces during the World War II Normandy Campaign in June 1944.
ornithischian V.or-no-'this-ke-snV Any of the “bird-hipped” dinosaur species (order Omithischia), herbivores with hip bones arranged like those of modern birds, with the pubis bone pointed backward. Many species had a toothless, horny beak and powerful cheek teeth. Omithischians flourished from the Late Triassic to the Late Cretaceous Epoch (227-65 million years ago). Many species (in the suborder Cerapoda) were bipe¬ dal and had ornate skull structures. Some were quadrupedal, with a mas¬ sive head culminating in a great bony frill. Other quadrupeds (in the suborder Thyreophora) had small heads and were heavily plated and armoured along the back, and some had armour on the flanks and head as well. See also protoceratops; saurischian; stegosaur; triceratops.
ornithology Branch of zoology dealing with the study of birds. Early writings on birds were largely anecdotal (including folklore) or practical (e.g., treatises on falconry and game-bird management). From the mid- 18th century on, ornithology progressed from the description and classi¬ fication of new species discovered in scientific expeditions to the examination of internal anatomy to the study of bird ecology and ethology. Ornithology is one of the few scientific fields in which nonprofessionals make substantial contributions; the field observations of birders provide
valuable information on behaviour, ecology, distribution, and migration. Other information is gained by means of radar, radio transmitters, portable audio equipment, and bird banding, which provides information on longevity and movements.
orogeny \6-'ra-jo-ne\ Mountain¬ building event, generally one that occurs in a geosyncline. Orogeny tends to occur during a relatively short geologic time frame. It is usu¬ ally accompanied by folding and faulting of strata and by the deposi¬ tion of sediments in areas adjacent to the orogenic belt. Orogenies may result from continental collisions, the underthrusting of continents by oce¬ anic plates, the overriding of oceanic ridges by continents, and other causes. See also Acadian orogeny, Alleghenian orogeny, Alpine orogeny, Laramide orogeny, Taconic orogeny.
Oromo \6-'ro-mo\ pejorative Galla Major ethnic group of Ethio-
Secretary decorated with ormolu mounts, marquetry, and intarsia, French, c. 1770; in the Wallace Collec¬ tion, London
COURTESY OF TRUSTEES OF THE WALLACE COLLECTION, LONDON
© 2006 Encyclopaedia Britannica, Inc.
Orontes River ► orthogonality I 1419
pia, numbering more than 20 million, or nearly one-third of the popula¬ tion, and occupying much of its central and south-central regions. They speak a Cushitic language of the Afroasiatic family. They are a diverse group, having assimilated and intermarried with other peoples since the 16th century. Traditionally the Oromo were nomadic herders, but today most are settled agriculturalists. Politically they are largely subjugated to the dominant Amhara. In religion they are divided among Islam, the Ethio¬ pian Orthodox faith, and traditional beliefs.
Orontes \o-'ran-tez\ River River, Middle East. Rising in the Biqa c Val¬ ley of Lebanon and flowing north between the Lebanon and Anti-Lebanon mountains, it passes the cities of Hims and Hamah in Syria, where it has been dammed to form Hims Lake. Northwest of Hamah it enters Turkey, where it flows west past the ancient city of Antioch and empties into the Mediterranean Sea. It is unnavigable for most of its 355 mi (571 km) length but is an important source of water for irrigation.
Orozco Vo-'ros-koV Jose Clemente (b. Nov. 23, 1883, Ciudad Guzman, Mex.—d. Sept. 7, 1949, Mexico City) Mexican mural painter. When he lost his left hand at 17, he abandoned architectural studies for painting, pursuing Mexican themes. As a caricaturist for a revolutionary paper, he explored Mexico City’s slums and painted a series of waterco¬ lours, House of Tears, on the lives of prostitutes. The reaction of moral¬ ists forced him to flee to the U.S. in 1917, but in 1919 the new government of Alvaro Obregon welcomed him back, and he joined Diego Rivera and David Alfaro Siqueiros in creating large-scale murals for public buildings, in which he continued his radical social commentary. Again forced to abandon Mexico in 1927, he worked until 1934 in the U.S., where his style evolved and matured in murals from coast to coast. In 1934, his international reputation firmly established, he returned to Mexico and embarked on his most technically impressive and emotionally expressive murals, including Catharsis (1934), in the Palacio de Bellas Artes. He was a leader among those who raised Mexican art to a position of inter¬ national eminence.