By a curious freak of nature, the tendency of the channel of the Mississippi is always toward one or the other of its banks, being influenced by the direction of its bends. The principle is one of nicely regulated refraction. If the river were perfectly straight, the gravity and inertia of its waters would move in a right line, with a velocity beyond all control. But we find the river very sinuous, and the momentum of current consequently lessened. For example, striking in an arm of the river, by the inertia of the moving volume, the water is thrown, and with less velocity, upon the opposite bank, which it pursues until it meets another repellent obstacle, from which it refracts, taking direction again for the other side. Above the Missouri, the river is principally directed by the natural trough of the valley. Below this, however, the channel is purely the work of the river itself, shaped according to the necessities of sudden changes or obstructions. This is proven by the large number of old and dry beds of the river frequently met with, the channel having been diverted in a new direction by the accumulation of sediment and drift which it had not the momentum to force out. Where the gravity of the greatest volume and momentum of water falls upon the bed of the river, there is described the thread of the channel, and all submerged space outside of this, though in the river, acts as a kind of reservoir, where eddies the surplus water until taken up by the current. And it always happens, where the channel takes one bend of the bed, a corresponding tongue of shallow water faces the indenture. Where the river, by some inexplicable cause, has been thrown from its regular channel, or its volume of water embarrassed by some difficulties along the banks, the effect is immediately perceived upon the neighboring bank. The column of water thus impinged against it at once acts upon the bank, and, singularly enough, exerts its strongest abrasive action at the bottom, undermining the bank, which soon gives way, and instead of toppling forward, it noiselessly slides beneath the water and disappears. Acres of land have thus been carried away in an incredibly short time, and without the slightest disruption of the serene flow of the mighty current. This carrying away of the banks, immense as is the amount of earth thrown into the waters of the river, has no sensible effect in blocking or directing the current, though it imperceptibly raises the channel. The force of the water does not permit its entire settlement in quantities at any one place, but distributes it along the bottom and shores below. Were this not the case, it is easily to be seen, the abrasion of the river banks would be greatly increased, and the destruction of the bordering lands immense.