DANUBE (Ger. Donau), the second of European rivers, inferior only to the Volga, has its origin in the 13rege and Brigach, two mountain-streams rising in' the eastern part of the Black Forest, in Baden, at an elevation of 2,850 ft. above sea-level in lat. 48' 6' n., and in long. 8° 9' east. The total length of the D. is about 1750 m.; the area which it drains is estimAted at 250,000 sq.m., comprising countries widely varying in climate and productions. The average fall of the D. is 18 in. per mile. At Ulm, it attains a breadth of 108 ft., and before its junction with the Sereth the mean breadth is 6,000 ft., and the depth, which at Ulm is 6 ft., and at Passau 16, is here on an average 20 feet. .The D. is joined in its course by sixty navigable rivers, and falls into the Black sea, pouring into it a volume of water nearly equal to that of all the other rivers that empty them selves there. From its source it flows in a north-easterly direction through Wurtcmberg and Bavaria. 'Passing Ulm, at which point the river becomes navigable for vessels of 100 tons, it receives from the s. the Lech and the Iser, with some unimportant streams from the n. ; flows rapidly past Ingolstadt, and onwards to Regensburg (Ratisbon); then suddenly altering its course, it proceeds in a south-easterly direction, passing Strau bing and Passau, where it enters the Austrian dominions. With little variation of course, the D. flows eastward from Passau to Presburg. receiving from the s. the Inn and the Ens, and from the n. the March or Morava, through a tract of country rich in min erals, well peopled, and highly cultivated. Near Linz. and also in the picturesque neigh borhood of Vienna, the waters of the D. frequently divide, and inclose large tracts of soil, forming islands, are the Great and Little Schutt, called also the "Golden Gardens." flurrying past Presburg, the D. alters its course to s.e.. and such is its velocity here., that barges can only navigate it downwards. Passing Pesth, and flowing directly s., it enters upon the Hungarian plain, a vast sandy and alluvial flat, in which it is continually forcing new channels and silting up old ones, sometimes sweep ing away towns, or capriciously removing its waters to a distance of several miles from such as were formerly built upon its banks. Here it receives from the n. the Waag and the Gran, while the Drave from the w. adds considerably to its volume. After this
accession the river turns towards the e., and joined by the waters of the Theiss and Temes from the n., sweeps past Belgrade, forming the boundary between Servia and Hungary. Still flowing eastward, the D., leaving Orsova, passes the famous "Iron Gate," a broad plateau of rock 1400 yards wide, over which the water formerly rushed with an overpowering noise. This rapid, which was followed by a series of whirlpools, eddies, and shallow falls, formed an effectual bar to the upward progress of vessels, no craft drawing more than 2} ft. of water being able to pass it. In 1847-19, however, the obstruction formed by the " Iron Gate" was to some extent removed by blasting, so that now vessels of 8, and even 9 ft. draught, can pass at certain seasons of the year, although the majority of vessels engaged on this part of the river draw no more than 4 ft. of water. A few milts further on, it enters a plain, and proceeding uninterruptedly, forms the boundary between Wallachia and Bulgaria. From the Carpathians it receives the Say] and the Aluta, and from Mt. Balkan the Morava. Increased by these rivers and by numberless streams, it progresses through a district fertile indeed, but badly cultivated and thinly peopled, occasionally broadening like a sea, as at Hirsova, and encircling many islands. After being joined by the Serail and the Pruth from the u., and after dividing into several branches forming deltoid islands, it flows eastward into the Black sea. The principal mouth is the Sulina, by which the greater number of ships enter. The D., which is the chief natural highway for European commerce, is through out the greater part of its course surrounded by picturesque and impressive scenery—at one time flanked with lofty mountains, again having on each side dense and far extending forests. At the peace of Paris, in 1856, the navigation of the Danube was declared free to all nations, and its management was intrusted to two commissions, one representing the European powers, another named by the states on the banks of the river. At the Berlin congress of 1878, it was stipulated that no ships of war should navigate the D. below the Iron Gate. The Danube steam navigation company, which has done much to increase the commerce, possesses upwards of 150 steamers and GOO tow-boats.