DANUBE, the largest and most considerable river in Europe, rising in the Black Forest, near Zunberg; and running north-east through Swabia, by Ulm, the capital of that country; then running east through Bavaria and Austria, passes by Ratisbon, Passau, Eas, and Vienna. It then enters Hungary, and runs south-east from Presburg to Buda, and so on to Belgrade; after which it divides Bulgaria from Wallachia and Moldavia, discharging itself by several channels into the Black sea, in the province of Bessarabia. Towards the mouth, it was called the Ister by the ancients; and it is now said, that four of the mouths are choked up with sand, and that there are only two remaining. It begins to be navigable for boats at Ulm, and receives several large rivers as it passes along. It is so deep between Buda and Belgrade, that the Turks and Christians have had men of war upon it; and yet it is not navigable to the Black sea, on account of the cataracts. The Danube was generally supposed to be the northern boundary of the Roman empire in Europe. It was worshipped as a deity by the Scythians.