680 DANUBE Passing again between two mountain ranges, the Leitha on the southern and the lesser Car- pathians on the northern bank, the Danube emerges into the fertile region of western Hun- gary. There, spreading out in several branches, it forms a great number of islands, among which the Great Schiitt (50 m. long) and the Little Schutt (27 m. long) are the largest. Through a defile, formed by the Nograd branch of the Carpathians and the Bakony Forest, the Danube enters the great Hungarian plain, turns abrupt- ly S. near Waitzen, and slowly winds through vast level bottom lands and marshes, until it meets the Sirmian range, and, having received the waters of the Drave, is again deflected toward the southeast. It then skirts the plain on the south till near Moldova, where it passes through the Transylvanian granite hills and the Servian limestone range. This pass (Kli- sura), 80 m. long, offers the greatest obstacles to the navigation of the Danube. Narrowed down to less than one half its former breadth, the river forms in seven places between Alibeg and Kladova rapids and whirlpools, of which those in the so-called Iron Gate, below Old Orsova, are the most violent. There it pours through a defile 7,500 ft. long and 650 wide, with a fall of 16 ft., and a rapidity of 10 to 15 ft. a second, over a number of reefs and ledges. After having been a terror to navigators for centuries, the Iron Gate has at last been ren- dered navigable for steamers, a channel having been cut through the ledge, by which vessels ply from Vienna to Galatz without a portage. In ancient times this portion of the river course was avoided by a canal, of which some vestiges still remain. Near Kladova the Danube enters the Bulgaro-Wallachian plains. From Tcber- netz to below Widin it runs nearly S., then turns E. Slowly rolling its muddy waters round the The Iron Gate of the Danube. extreme spurs of the Balkan, and forming numerous islands, it reaches a point only 32 m. from the sea, where it suddenly bends N. and flows upward of 100 in. to the junction with the Sereth ; thence again eastward ; at last, joined by the Pruth and divided into several branches, which sluggishly wind through a low and dreary alluvial country (the delta of the Danube), it empties into the Black sea by three principal channels, the Kilia, . Sulina, and St. George, and four lesser ones. The most im- portant tributaries of the Danube are, on the right or southern bank, the Iller, Lech, Isar, Inn, Traun, Enns, Leitha, Raab, Sarviz, Drave, Save, and Morava ; on the left bank, the Brenz, Warnitz, Altmuhl, Naab, Regen, Itz, March, Waag, Neutra, Gran, Eipel, Theiss, Temes, Aluta, Arjish, Yalomitza, Sereth, and Pruth. The principal towns on its banks are : in Wiir- temberg, Ulm ; in Bavaria, Ratisbon and Pas- sau ; in Austria proper, Linz and Vienna ; in Hungary, Presburg, Oomorn, Gran, Buda, and Pesth ; in the Military Frontier, Peter wardein and Orsova ; in Servia, Belgrade ; in Bulga- ria, Widin, Nicopolis, Rustchuk, Silistria, and Hirsova; in Rournania, Giurgevo, Braila, and Galatz. The Danube has through all history been of great political importance. For the Huns, the Avars, Bulgarians, Magyars, and Tartars, the Danube valley was the scene of efforts to subdue the Occident. While the progress of the barbarians was somewhat checked by the other great European rivers flowing N. and S., the Danube served as a highway to the west. The western nations having at last established their supremacy, the human current was reversed for the conquest of the Orient by the crusaders ; and during sue-
