the 18th century there were signs of improvement. Though the Danes temporarily occupied the town in 1801, it preserved its freedom and gained some of the chapter lands when the imperial constitution of Germany was broken up by the act of February 1803, while trade and commerce prospered for a few years. But in November 1806, when Blücher, retiring from the catastrophe of Jena, had to capitulate in the vicinity of Lübeck, the town was sacked by the French. Napoleon annexed it to his empire in December 1810. But it rose against the French in March 1813, was re-occupied by them till the 5th of December, and was ultimately declared a free and Hanse town of the German Confederation by the act of Vienna of the 9th of June 1815. The Hanseatic League, however, having never been officially dissolved, Lübeck still enjoyed its traditional connexion with Bremen and Hamburg. In 1853 they sold their common property, the London Steelyard; until 1866 they enlisted by special contract their military contingents for the German Confederation, and down to 1879 they had their own court of appeal at Lübeck. Lübeck joined the North German Confederation in 1866, profiting by the retirement from Holstein and Lauenburg of the Danes, whose interference had prevented as long as possible a direct railway between Lübeck and Hamburg. On the 27th of June 1867 Lübeck concluded a military convention with Prussia, and on the 11th of August 1868 entered the German Customs Union (Zollverein), though reserving to itself certain privileges in respect of its considerable wine trade and commerce with the Baltic ports.
See E. Deecke, Die Freie und Hansestadt Lübeck (4th ed., Lübeck, 1881) and Lübische Geschichten und Sagen (Lübeck, 1891); M. Hoffmann, Geschichte der Freien und Hansestadt Lübeck (Lübeck, 1889–1892) and Chronik von Lübeck (Lübeck, 1908); Die Freie und Hansestadt Lübeck, published by Die geographische Gesellschaft in Lübeck (Lübeck, 1891); C. W. Pauli, Lübecksche Zustände im Mittelalter (Lübeck, 1846–1878); J. Geffcken, Lübeck in der Mitte des 16ten Jahrhunderts (Lübeck, 1905); P. Hasse, Die Anfange Lübecks (Lübeck, 1893); H. Bödeker, Geschichte der Freien und Hansestadt Lübeck (Lübeck, 1898); A. Holm, Lübeck, die Freie und Hansestadt (Bielefeld, 1900); G. Waitz, Lübeck unter Jürgen Wullenweber (Berlin, 1855–1856); Klug, Geschichte Lübecks während der Vereinigung mit dem französischen Kaiserreich (Lübeck, 1857); F. Frensdorff, Die Stadt- und Gerichtsverfassung Lübecks im 12. und 13. Jahrhundert (Lübeck, 1861); the Urkundenbuch der Stadt Lübeck (Lübeck, 1843–1904); the Lübecker Chroniken (Leipzig, 1884–1903); and the Zeitschrift des Vereins für lübeckische Geschichte (Lübeck, 1860 fol.). (R. P.; P. A. A.)
LUBLIN, a government of Russian Poland, bounded N. by Siedlce, E. by Volhynia (the Bug forming the boundary), S. by Galicia, and W. by Radom (the Vistula separating the two). Area, 6499 sq. m. The surface is an undulating plain of Cretaceous deposits, 800 to 900 ft. in altitude, and reaching in one place 1050 ft. It is largely covered with forests of oak, beech and lime, intersected by ravines and thinly inhabited. A marshy lowland extends between the Vistula and the Wieprz. The government is drained by the Vistula and the Bug, and by their tributaries the Wieprz, San and Tanev. Parts of the government, being of black earth, are fertile, but other parts are sandy. Agriculture is in good condition. Many Germans settled in the government before immigration was stopped in 1887; in 1897 they numbered about 26,000. Rye, oats, wheat, barley and potatoes are the chief crops, rye and wheat being exported. Flax, hemp, buckwheat, peas, millet and beetroot are also cultivated. Horses are carefully bred. In 1897 the population was 1,165,122, of whom 604,886 were women. The Greek Orthodox (chiefly Little Russians in the south-east) amounted to 20.1% of the whole; Roman Catholics (i.e. Poles) to 62.8%; Jews to 14.2%; and Protestants to 2.8%. The urban population was 148,196 in 1897. The estimated population in 1906 was 1,362,500. Industrial establishments consist chiefly of distilleries, sugar-works, steam flour-mills, tanneries, saw-mills and factories of bent-wood furniture. Domestic industries are widely developed in the villages. River navigation employs a considerable portion of the population. The government is divided into ten districts, the chief towns of which, with their populations in 1897, are—Lublin, capital of the province (50,152); Biegoray (6286); Cholm (19,236); Hrubieszow (10,699); Yanów (7927); Krasnystaw or Kraznostav (8879); Lubartow (5249); Nova-Alexandrya or Pulawy (3892); Samostye (12,400); and Tomaszów (6224).
LUBLIN, a town of Russian Poland, capital of the government of the same name, 109 m. by rail S.E. of Warsaw, on a small tributary of the Wieprz. Pop. (1873) 28,900; (1897) 50,152. It is the most important town of Poland after Warsaw and Lodz, being one of the chief centres of the manufacture of thread-yarn, linen and hempen goods and woollen stuffs; there is also trade in grain and cattle. It has an old citadel, several palaces of Polish nobles and many interesting churches, and is the headquarters of the XIV. army corps, and the see of a Roman Catholic bishop. The cathedral dates from the 16th century. Of the former fortifications nothing remains except the four gates, one dating from 1342.
Lublin was in existence in the 10th century, and has a church which is said to have been built in 986. During the time the Jagellon dynasty ruled over Lithuania and Poland it was the most important city between the Vistula and the Dnieper, having 40,000 inhabitants (70,000 according to other authorities) and all the trade with Podolia, Volhynia and Red Russia. Indeed, the present town is surrounded with ruins, which prove that it formerly covered a much larger area. But it was frequently destroyed by the Tatars (e.g. 1240) and Cossacks (e.g. 1477). In 1568–1569 it was the seat of the stormy convention at which the union between Poland and Lithuania was decided. In 1702 another convention was held in Lublin, in favour of Augustus II. and against Charles XII. of Sweden, who carried the town by assault and plundered it. In 1831 Lublin was taken by the Russians. The surrounding country is rich in reminiscences of the struggle of Poland for independence.
LUBRICANTS. Machines consist of parts which have relative motion and generally slide and rub against each other. Thus the axle of a cart or railway vehicle is pressed against a metallic bearing surface supporting the body of the vehicle, and the two opposed surfaces slide upon each other and are pressed together with great force. If the metallic surfaces be clean, the speed of rubbing high, and the force pressing the surfaces together considerable, then the latter will abrade each other, become hot and be rapidly destroyed. It is possible, however, to prevent the serious abrasion of such opposing surfaces, and largely to reduce the frictional resistance they oppose to relative motion by the use of lubricants (Lat. lubricare, lubricus, slippery). These substances are caused to insinuate themselves between the surfaces, and have the property of so separating them as to prevent serious abrasion. The solid and semi-solid lubricants seem to act as rollers between the surfaces, or form a film between them which itself suffers abrasion or friction. The liquid lubricants, however, maintain themselves as liquid films between the surfaces, upon which the bearing floats. The frictional resistance is then wholly in the fluid. Even when lubricants are used the friction, i.e. the resistance to motion offered by the opposing surfaces, is considerable. In the article Friction will be found a statement of how friction is measured and the manner in which it is expressed. The coefficient of friction is obtained by dividing the force required to cause the surfaces to slide over each other by the load pressing them together. For clean unlubricated surfaces this coefficient may be as great as 0.3, whilst for well-lubricated cylindrical bearings it may be as small as 0.0006. Engineers have, therefore, paid particular attention to the design of bearings with the object of reducing the friction, and thus making use of as much as possible of the power developed by prime movers. The importance of doing this will be seen when it is remembered that the energy wasted is proportional to the coefficient of friction, and that the durability of the parts depends upon the extent to which they are separated by the lubricant and thus prevented from injuring each other.
There is great diversity in the shapes of rubbing surfaces, the loads they have to carry vary widely, and the speed of rubbing ranges from less than one foot to thousands of feet per minute. There is also a large number of substances which act as lubricants,
