Numerous tributaiies join tho Rhine in its upper course above Basel, but none of them is navigable or otherwise important, with the exception of the Aar, which with its feeders the Reuss and the Limmat, hrings Into the Rhino the drainage of the greater past of Switzerland. [Ammo.] Middle Mina—At Basel, where this division of the river begins, it has entirely left the mountain region of the Alps and Jura Mountains, and at the same time it changes its western into a north-north-eastern and northern course. It flow, in a valley from 40 to 50 miles wide, extending between the Black Forest (Schwarzwald) and the mountains connected with it on the met, on the one side, and the Vosges and their northern prolongation the Hardt Mountains on the west, from Basel to Mainz, a distance of nearly 200 miles. At Mainz the surface of the river is only 274 feet above the sea. Between Three) and Strasbourg, a distance of only about 80 miles, the fall of the river is not less than 347 feet, or 41 feet per mile. Accordingly the current is very rapid, and in addition to this the wide bed of the river contains numerous sand-banks and small islands, which are subject to sudden and frequent changes in their form and position, so that navigation in this part of the Rhine is dangerous and therefore limited. Between Kehl opposite Straahourg, and Germersheim, which places are about 50 miles distant from one another, the islands increase in size, and are lase subject to change. Few islands occur north of Germersheim, and the ricer flows slowly, making' large bends. The largest kind of barges used between Strasbourg and Mainz are of 100 tons burden, but in ascending they must be drawn up, which is chiefly done by horses.
Between Mainz and Bonn the Rhino runs between two mountain regions in a narrow valley. This valley, which contains some of the most picturesque scenery on the continent of Europe, is in some parts so narrow, that there is hardly level space enough for a road between the mountains and the banks of the river. The hills along the banks of the stream contain extensive vineyards, the produce of which is known all over Europe under the name of Rhenish wines. At Bingin a ledge of rocks crosses the river, and though the Prussian govern ment has somewhat lessened the danger by blasting some of the rocks, neither bargee nor steam-boata can pass by night or in foggy weather. Near Bachsrach, farther down, there is a group of rocks, and opposite St. Goer another ledge. At Cologne the river is only 110 feet above the sea-level. The ascent by bargee is very tedious.
Numerous tributaries join the Rhine in its middle course. Those which flow into it from the west have a short course, and are not navigable, with the exception of the Moselle, which rises on the western slopes of the Vosges, and runs first north-west, and then north, but the greater part of its course is to the north-east. After a course of 320 miles, it joins the Rhine at Coblenz. [1Ioszat.r..] The lower part of its course lies in a deep valley of moderate width, inclosed by hills and mountains, the slopes of which are covered with extensive vineyards, which produce the Moselle wine.
The number of navigable rivers which join the Rhine in its middle course from the right ie much greater. The most southern is the Neckar, which rises near 48' N. lat., in the mountainous tracts by which the range called the Rauhe Alp is connected with the Black Forest, and after a course of about 170 miles falls into the Rhine at Mannheim. [Sioux-Kans.)
The most important of the aftluenta of the Middle Rhine is the Main or Maya, which falls into it opposite Mainz. Its sources are in the Fichtelgebirge, not fir from the boundary of Bohemia., where it originates in two branches, of which the northern is called the White and the southern the Red Main. The two branches unite about two miles and a half below liulmbech, and begin to change their western course into a southern. Not far from Bamberg the river is joined by its only navigable affluent, the Rednitz : it then flows west by north to Schweinfurt, whence it again runs south to Markbreit, and from that place to the north-north-west to Gemtinden. From Gemanden it again flows southward, and making a wide sweep, encircles the mountain region of the Speseart. At Henan it turns westward, and passing near Frankfort in that direction, joins the Rhino. Though its sources are only about 150 miles from its mouth, the whole course exceeds 360 miles, owing to the numerous large bends. River barges ascend above the mouth of the Rednitz, more than 250 miles from its mouth; and from Kitzingen downwards, it is navigated by vessels of 100 tons burden. The whole course lies through a hilly but rather fertile and well-cultivated country. As no high hills intervene between the Main and the Danube, a canal, origi nally projected by Charlemagne, was cut by the exiting Ludwig of Bavaria from Forchheim along the banks of the Rednitz and those of the Altartibl, a feeder of the Danube. This canal establishes a water communication between the North Sea and the Black Sea.
Farther north the Rhine is joined by the Lohn, which falls into it a little above the mouth of the Moselle at Niederlahnstein : it flows about 140 miles, and is navigable for moderate4ized river boats to Diez, about 20 miles from its mouth. It traverses a very hilly country. The river Sieg, which falls into the Rhine below Bonn, flows about 70 miles, and is navigable to Siegburg, which is about eight miles from its month. [AnNsneitn.] Lower filline.—From Cologne to its mouths, a distance of about 300 miles, the course of the Rhine is through a low level country, though the western declivity of the hills of the Sauerland are near its eastern bank, between Cologne and Dibiseldorf. The current is extremely gentle, as the whole fall does not amount to much more than four inches per mile, the surface at Cologne being, as already observed, only 110 feet above the sea-level. From this town down wards the Rhine in navigated by sea-going ships, many of which are built in the ship-yards of Cologne. [Cozowsz.] About 200 miles from Its mouth, and soon after it has entered Holland, the Rhine begins to divide Into several arras; but before this division, the waters are increased by three navigable rivers, on the left bank by the Erft, which has a course of about 60 miles, and on the right bank by the Ruhr, whose course is above 100 miles, about one-half of which has been made navigable for barges by the construction of several locks, and the Lippe, which is somewhat more than 100 miles long, and is navigated from Lippstadt by small river-boats, and from Liinen by large ones.