RHINE 287 river is 1,280 ft. above the sea, and the falls vary from 60 to 75 ft. in height. Below these falls the general course is still westerly, but very tortuous; and the river flows between mountains for about 50 m. to Laufenburg, where the navigation is again interrupted by a cataract. The bed is here narrowed to about 50 ft., and boats ascend and descend by means of ropes after being unloaded. About 10 m. below Laufenburg there is a rapid of considerable length, which is exceeding- ly dangerous, though it does not stop navi- gation. This is the last impediment to the navigation of the upper Rhine. Below this rapid the level of the river is 850 ft. above the sea, and it is only 50 ft. less at Basel. Above this point the Rhine receives numerous tributaries, the most important being the Aar, which, emptying about 12 m. above Laufen- burg, brings the drainage of the greater part of Switzerland. From the lake of Constance to Basel the Rhine forms the boundary line between Baden and Switzerland. Where the middle Rhine begins at Basel, the river has left the mountainous region, and changed its course to a northerly direction. It flows for about 200 m., to Mentz, through a valley from 30 to 50 m. wide, extending between the Black Forest and other mountains on the east, and the Vosges and the Hardt mountains on the west, forming the boundary line between Ba- den and Alsace, and Baden and Rhenish Ba- varia, and passing through Hesse-Darmstadt. Between Basel and Strasburg, about 80 m., the fall of the river is 4J- ft. per mile, and the current very rapid. The bed is wide and ob- structed by numerous movable sand banks and small islands, which render the navigation in- tricate and dangerous. For the next 60 m., to Germersheim, the islands increase in size and are less liable to shift their position. Gold is washed from the sand and gravel along this part of its course, but not in paying quantities. Below Germersheim islands are rare, and the river flows sluggishly in large bends to Mentz, where its surface is only about 250 ft. above the sea. Many of the isthmuses formed by these bends have been cut through of late years, so as to shorten its course. Between Strasburg and Mentz it is navigable for boats of about 100 tons burden, which descend with the current, but in going up are tracked chief- ly by horses. Between Mentz and Cologne, about 120 m., the course of the river is first "W., then N. 1ST. W., and afterward mostly N. W. It first forms the boundary between Hesse- Darmstadt and the Prussian province of Hesse- Nassau, and then between the latter and the Prussian Rhine province, which it enters near Coblentz. This part of the river runs be- tween two mountain regions, where in many places the hills come so close to the banks of the river that there is scarcely room for a road. The produce of the extensive vineyards in this neighborhood is known as Rhenish wines. There is a ledge of rocks at Bingen which pre- 703 VOL. xiv. 19 vents steamers and barges from passing during foggy weather or at night. The surface of the water at Cologne is 120 ft. above the sea. During its middle course the Rhine receives many tributaries ; but, with the exception of the Moselle, those from the west are all short and not navigable. On the right or E. side the tributaries are much larger and more nu- merous, the most important being the Neckar, Main, Lahn, and Sieg. The lower Rhine ex- tends for about 300 m. from Cologne to its mouths, and flows through a low level country, with the hills of Sauerland near its E. bank between Cologne and Dusseldorf. From Co- logne to Wesel its course is mostly N. N. W., though very tortuous. From Wesel to the frontiers of Holland it flows N. W. Below Cologne the Rhine is navigable for sea-going vessels, and the fall from thence to its mouth is only about 4 in. in a mile, and the current extremely sluggish. Shortly after entering Holland, near the village of Pannerden, the Rhine divides into two arms, the southern of which takes the name of Waal, the northern preserving that of Rhine. The Waal, which joins the Maas, is here 210 yards broad, while the Rhine is only 114 yards, and about two thirds of the volume of water runs into the former. After the separation the Rhine flows N. N. W., and near Arnhem, 12 m. lower down, it again divides into the Yssel, which runs N. to the Zuyder Zee, and the Rhine, which flows W. At Wyck, about m. lower down, the Rhine divides for the third time, into the Leek and Kromme Ryn (Crooked Rhine), the former of which is the larger. The Kromme Ryn runs N. W. to Utrecht, where the last division takes place, into the Vecht, which flows to the Zuyder Zee, and the Oude Ryn (Old Rhine), which continues westward past Leyden. The mouth of the Oude Ryn was formerly obstructed by dunes or sand hills, and the river did not reach the sea ; but in 1807 a canal was cut through them, and it now communicates with the North sea at Katwyk, a few miles N. W. of Leyden. Be- fore it begins to form the delta the lower Rhine is augmented by the Erft, Ruhr, and Lippe, all of which are navigable. The Yssel was originally a canal cut by Drusus to unite the Rhine with the river now called Oude Yssel (Old Yssel). The Leek, or middle branch of the Rhine, was also originally a canal made by the Roman general Corbulo ; but in A. D. 839 its bed was so much enlarged by a flood that it became the main stream. The delta of the Rhine is bounded N. by the Zuyder Zee, E. by the Yssel, S. by the Waal and Maas, and W. by the North sea ; it comprehends the three Dutch provinces of North and South Holland and Utrecht, and about two thirds of Gelder- land, all of which country would be subject to inundations were it not protected by em- bankments. These embankments begin in the Prussian district of Dusseldorf, extend along the banks of the different arms of the Rhine
