UNDULATORY THEORY, the theory that light is due to vibrations or undulations in the ether as the medium through which it is transmitted from its source in a luminous body.

UNEARNED INCREMENT, increase in the value of land or any property without expenditure of any kind on the part of the proprietor.

UNICORN, a fabulous animal like a horse, with a cubit and a half long horn on the forehead; was adopted by James I. as the symbol of Scotland on the royal arms; is in Christian art a symbol of the incarnation, and an emblem of female chast.i.ty.

UNIFORMITY, ACT OF, an Act pa.s.sed in England in 1662 regulating the form of public prayers and rites to be observed in all churches, and which had the effect of driving hundreds of clergymen from the Established Church.

UNIGENITUS, THE BULL, a bull beginning with this word, issued by Pope Clement XI. in 1713 against JANSENISM (q. v.) in France, and which was in 1730 condemned by the civil authorities in Paris.

UNION, FEDERAL, name given to a union of several States in defence or promotion of the common good, while each State is independent of the rest in local matters.

UNION, THE, a name applied in the English history to (1) the Union of England and Scotland in 1603 under one crown, by the accession of James VI. of Scotland to the throne of England on the death of Elizabeth; (2) the Union of England and Scotland in 1707, under one Parliament seated at Westminster, into the United Kingdom of Great Britain; and (3) to the Union of the United Kingdom of Great Britain to Ireland in 1801, when the Irish Parliament was abolished, and was represented, as it still is, in the Imperial.

UNION JACK, originally the flag of Great Britain, on which the crosses of St. George and St. Andrew are blended, with which certain white streaks were blended or fimbriated after the Union with Ireland.

UNIONISTS, name given to the Liberal party opposed to Mr.

Gladstone's measure to grant Home Rule to Ireland.

UNITARIANS, a designation applicable to all monotheists in religion, including Jews and Mohammedans, but generally and more specially applied to those who deny the Church doctrine of the Trinity, and in particular the divinity of Christ, and who have at different times and in different countries a.s.sumed an att.i.tude, both within the pale of the Church and outside of it, of protestation against the opposite orthodox creed in the interests of rationalistic belief; the name is also employed in philosophy to designate those who resolve the manifold of being into the operation of some single principle.

UNITED BRETHREN, name given to the MORAVIANS (q. v.).

UNITED PRESBYTERIANS, a body of Presbyterians in Scotland who dissent from the Established Church on chiefly ecclesiastical grounds, and had their origin in union in 1847 of the Secession Church of 1733 with the Relief Church of 1752, bodies previously in dissent as well. A further union of the United Presbyterian body with the Free Church is to all appearance about to be consummated.

UNITED PROVINCES. See HOLLAND.

UNITED STATES (62,622), the great Western republic; occupies an area nearly as large as all Europe, bounded on the N. by the Dominion of Canada, on the E. by the Atlantic, on the S. by Mexico and the Gulf, and on the W. by the Pacific, extending 2700 m. from E. to W., and on an average 1600 m. from N. to S.; on the coasts are few capes, inlets, and islands, except on that of New England; there are two great mountain systems, the Appalachians on the E. and the Rockies, the Cascade ranges, &c., on the W., which divide the territory into four regions--an eastern, which slopes from the Appalachians to the Atlantic, a manufacturing region; a central, which slopes S., formed by the Mississippi Valley, an agricultural and pastoral region; a plateau supported by the Rocky and Cascade ranges, a metalliferous region; and a territory with the valley of the Sacramento, which slopes to the Pacific, of varied resources. The great rivers are in the Mississippi Valley, as also the two largest lakes, the Michigan and Great Salt Lake, though there are important rivers both for navigation and water-power on the Atlantic and Pacific slopes. The climate is of every variety, from sub-arctic to sub-tropic, with extremes both as regards temperature and moisture, in consequence of which the vegetation is varied. The mineral wealth is immense, and includes, besides large beds of coal, all the useful metals. The industries, too, are manifold, and embrace manufactures of all kinds, with agriculture, grazing, mining, and fishing, while commerce is prosecuted with an activity that defies all rivalry, the facilities in railway and waterway being such as no other country can boast of, for there are over 182,000 miles of railway, not to mention street railways and traction lines, with telegraphic and telephonic communication. The population is mostly of British and German descent, with eight million negroes, who are all English-spoken. The Government is a federal republic of 45 States; the legislature consists of two Houses--a Senate representing the States, each one sending two members, and a House of Representatives representing the people, every citizen over 21 having a vote, and every 170,000 voters having a representative--the head of the Government being the President, elected for a term of four years, and commander-in-chief of both army and navy. Religious equality prevails through all the States, though the Protestant section of the Church is in the ascendant, and education is free and general, though backward in some of the former slave-holding States, the cost being met by State or local funds, supplemented by the Federal Government.

UNITED STATES, PRESIDENTS OF, George Washington (1789-1797); John Adams (1797-1801); Thomas Jefferson (1801-1809); James Maddison (1809-1817); James Munroe (1817-1825); John Quincy Adams (1825-1829); Andrew Jackson (1829-1837); Martin Van Buren (1837-1841); John Tyler (1841-1845); John K. Polk (1845-1849); Zachary Taylor (1849-1850); Millard Fillmore (1850-1853); Franklin Pierce (1853-1857); James Buchanan (1857-1861); Abraham Lincoln (1861-1865); Andrew Johnson (1865-1869); Ulysses D. Grant (1869-1877); Rutherford B. Hayes (1877-1881); James A.

Garfield (1881); Chester A. Arthur (1881-1885); Grover Cleveland (1885-1889); Benjamin Harrison (1889-1893); Grover Cleveland (1893-1897); William McKinley (1897-1901); Theodore Roosevelt (1901).

UNITIES, THREE, name given to the rule laid down by Aristotle that a tragedy should be limited to one subject, to one place, and a single day.

UNIVERSALISTS, a body of Christians who profess to believe in the final restoration of all the fallen, angels as well as men; a body chiefly of American growth, having an ecclesiastical organisation, and embracing a membership of 40,000; there are many of them Unitarians, and all are more or less Pelagian in their views of sin.

UNKNOWN, THE GREAT, name given to Sir Walter Scott from withholding his name in publishing the Waverley novels.

UNTERWALDEN (27), a canton of Switzerland S. and E. of Lucerne, consisting of two parallel valleys 15 m. long running N. and S.; an entirely pastoral country, and exports articles of husbandry.

UNYANYEMBE, a district of German East Africa, with a town of the name, with a settlement of Arabs who cultivate the soil, the fruits of which they export.

UNYORO (1,500), a native State of Central Africa, between Lake Albert Nyanza and the territory of Uganda.

UPAN'ISHADS (Instructions), a voluminous heterogeneous collection of treatises connected with the Vedas, and the chief source of our knowledge of the early metaphysical speculations and ethical doctrines of the Hindus; they are to a great extent apocryphal, and are posterior to the rise of Buddhism.

UPAS TREE, a poison-yielding-tree, at one time fabled to exhale such poison that it was destructive to all animal and vegetable life for miles round it.

UPOLU (16), the princ.i.p.al island in the SAMOAN GROUP (q. v.), is 140 m. in circ.u.mference, and rises in verdure-clad terraces from a belt of low land on the sh.o.r.e, with Apia, the capital of the group, on the N. border.

UPPINGHAM, market-town in Rutland, with a famous public school.

UPSALA (21), the ancient capital of Sweden, on the Sala, 21 m. NW.

of Stockholm, the seat of the Primate, and of a famous university with 1900 students, and a library of 250,000 volumes; its cathedral, built of brick in the Gothic style, is the largest in Sweden, contains the tombs of Linnaeus and of Gustavus Vasa.

URAL, a river of Russia, which rises in the E. of the Urals and forms part of the boundary between Europe and Asia, and falls after a course of 870 m. by a number of mouths into the Caspian Sea.

URALS, THE, a range of mountains rich in precious as well as useful metals, extending from the Arctic Sea to the Sea of Aral, and separating European from Asiatic Russia, and is 1330 m. in length, 60 m. in breadth, and 3000 ft. in average height.

URALSK (26), a town, a Cossack centre, on the Ural River, 280 m.

from the Caspian Sea, and a place of considerable trade.

URANIA, the muse of astronomy, is represented with a globe in her hand, to which she points with a small rod.

URa.n.u.s, a planet, the outermost but one of the solar system, is 1770 millions of miles from the sun, takes 30,686 of our days, or 84 of our years, to revolve round it, has four times the diameter of the earth, and is accompanied by four moons; it was discovered in 1781 by Herschel, and called by him Georgium Sidus in honour of George III.

URa.n.u.s (Heaven), in the Greek mythology the son of Gaia (the Earth), and by her the father of the t.i.tans; he hated his children, and at birth thrust them down to Tartarus, to the grief of Gaia, at whose instigation Kronos, the youngest born, unmanned him, and seized the throne of the Universe, to be himself supplanted in turn by his son Zeus.