OESEL (51), a marshy, well-wooded island at the mouth of the Gulf of Riga, in the Baltic, 45 m. long and 25 m. of average breadth; has some low hills and precipitous coasts; Arensburg (4), on the SE. shore, is the only town; Danish from 1559, the island passed to Sweden in 1645 and to Russia in 1721; the wealthier classes are of German descent.

OFFA’S DYKE, an entrenchment and rampart between England and Wales, 100 m. long, extending from Flintshire as far as the mouth of the Wye; said to have been thrown up by Offa, king of Mercia, about the year 780, to confine the marauding Welsh within their own territory.

OFFENBACH, JACQUES, a musical composer, born at Cologne, of Jewish parents, creator of the opera bouffe; was the author of “La Belle Helene,” “Orphee aux Enfers,” “La Grande Duchesse,” “Madame Favart,” &c. (1810-1880)

OFFERTORY, in the Roman Catholic Church a portion of the liturgy chanted at the commencement of the eucharistic service, also in the English the part of the service read during the collection of the alms at communion.

OFTERDINGEN, HEINRICH VON, a famous MINNESINGER (q. v.) of the 15th century.

OGHAM or OGAM, an alphabet of 20 letters in use among the ancient Irish and Celts, found carved on monumental stones in Ireland, Wales, Cornwall, and the North of Scotland.

OGLETHORPE, JAMES EDWARD, English general, born in London; served in the Marlborough wars, sat in Parliament for several years, conceived the founding of a colony for debtors in prison, and founded Georgia; returning to England, fought against the Pretender, and died in Essex (1696-1785).

OGOWE`, a West African river, 500 m. long, rises in the Akukuja plateau, and following a semicircular course northward and westward enters the Atlantic by a delta at Cape Lopez, its course lying wholly within French Congo territory; in the dry season its volume is much diminished, and its many sandbanks prevent its navigation except by small boats.

O’GROAT’S HOUSE, JOHN.  See JOHN O’ GROAT’S HOUSE.

OGYGES, a Boeotian autochthon, the legendary first king of Thebes, which is called at times Ogygia, in whose reign a flood, called the Ogygian after him, inundated the land, though some accounts make it occur in Attica.

OGYGIA, a mythological island of Homeric legend, situated far off in the sea, and the home of the sorceress CALYPSO (q. v.).

OHIO (3,672), a State of the American Union, a third larger than Scotland, stretches northward from the Ohio River to Lake Erie, between Pennsylvania and Indiana.  It consists of level and undulating plains, on which are raised enormous crops of wheat and maize.  Sheep-grazing and cattle-rearing are very extensive; its wool-clip is the largest in America.  There are valuable deposits of limestone and freestone, and in output of coal Ohio ranks third of the States.  The manufactures are very important; it ranks first in farm implements, and produces also wagons, textile fabrics, and liquors.  In the N. excellent fruit is grown.  The capital is Columbus (88), the largest city is Cincinnati (297).  Admitted to the Union in 1803, it boasts among its sons four Presidents—­Grant, Hayes, Garfield, and Benjamin Harrison.