After receiving the Missouri, next enters the Ohio. The water of this river is less impregnated than the Missouri, though not by any means free from silt. The country through which it flows is mountainous, and the soil hard, and does not afford the same facility of abrasive action as that of the other rivers. From the mouth of the Ohio, the Mississippi pursues a course of nearly four hundred miles, when it receives the turbid waters of the White and Arkansas Rivers. In the intervening distance a large number of small currents, more or less largely sedimentary, according to the character of the country through which they run, enter the Mississippi, in the aggregate adding materially to the sediment of the receiving stream. The White and Arkansas carry in their waters a large amount of unprecipitated matter. In this vicinity, too, sets in that singular system of natural safeguards of the surrounding country, the bayous. The country here also changes its appearance, becoming flat and swampy, and in some parts attaining but a few feet above the flood of the river, whereas in other parts, as we approach the Gulf, the country is even lower than the river. The miasmatic and poisonous water of the Yazoo next enters, about ten miles above Vicksburg. This river is more deeply impregnated with a certain kind of impurities than any other tributary of the Mississippi. The waters are green and slimy, and almost sticky with vegetable and animal decomposition. During the hot season the water is certain disease, if taken into the stomach. The name is of Indian origin, and signifies 'River of Death.' The Yazoo receives its supply from bayous and swamps, though it has several considerable tributaries. Below the Yazoo, on the west side, enters the Red. The name indicates the peculiar caste of its water. This river carries with it the washings of an extensive area of prairies and swamps, and is the last of the great tributaries. Hence the tendency of streams is directly to the Gulf, and that network of lateral branches, of which we will hereafter speak, begins. We have only considered the most prominent tributaries: the sediment also brought down by the numerous smaller streams is very great, and makes great additions to the immense buoyant matter of the Mississippi. The river itself from its own banks scours the larger portion of the sediment it contains; and in so gigantic a scale is this carried on, that it can be seen without the exercise of any very remarkable powers of sight. It is not by the imperceptible degrees usually at work in other streams, but often involves in its execution many acres of adjoining land. It will be interesting to consider this more fully.