The principal bayous, which exert so important a part in regulating the stage of this part of the river, are in length and distance from the Gulf as follows: _Distance By River._ _Miles._ _Miles._ Bayou La Fourche, from the Mississippi River to the Gulf, 100 180 " Plaquemine, " " " 60 210 " Manchac, " " " 50 220 " Atchafalaya, " " " 110 300 The course of the bayous, it will be seen, have a more direct route than the river. Their average width is one thousand feet, and fall twenty-two feet. Their average velocity is about three and two tenths miles per hour. Though the rise of the river at Baton Rouge sometimes attains a height of thirty feet, so great is the relieving capacity of these lateral branches, that at New Orleans the rise never exceeds twelve feet. At Point a la Hache the difference between the highest and lowest stage is but six feet; at Fort Jackson, four feet, while it falls to low water mark when it enters the sea. Having briefly noted the peculiarities of the Mississippi, a few facts in recapitulation may place it in a more comprehensive attitude as regards its appearance and size. In the north, after leaving the Falls of St. Anthony, the river has but the characteristics of a single stream, but below the Ohio we find it combines the peculiarities of a number. The water here begins to show signs of almost a new nature and greater density. The river develops into a much wider channel, and its peculiarities become more marked and impressive. Strange as it may seem, the greatest mean width of the Lower Mississippi is at the confluence of the Ohio, and from this point it gradually becomes narrower, until it is but little more than half that width as it draws near the Gulf. This gives the river a kind of funnel shape, and if it were not for the numerous bayous and lateral branches, which we have explained, the most violent convulsion and devastation would arise. In the United States Engineer Reports we find this statement: The mean width of the Mississippi River between the Ohio _Feet._ and Arkansas Rivers, 4,500 Mean width between the Arkansas and Red Rivers, 4,100 Mean width between the Red River and Donaldsonville, 3,000 Mean width between Donaldsonville and the Gulf, 2,500 Above the Red River the range between high and low water is about forty-five feet, and thence to the Gulf it gradually diminishes to zero. The greatest velocity of current is about five and a half miles per hour during floods, and about one and a half miles per hour during low water.