annual excess of water in the Mississippi, nature has
provided sure safeguards. These are termed bayous, and are found
everywhere along the river, below the mouth of the Ohio. Additional
preventives against inundation are the lagoons, or sea-water lakes, of
the coast. Into these bayous and lagoons, as the river becomes high, the
excess of water backs or flows. They are natural reservoirs, to ease the
rise, and prevent the inevitable suddenness and danger which would
result without them. In these reservoirs the water rises or falls with
the river; and when the fall becomes permanent, the water in the
bayous--the lagoons having outlet into the sea--falls with it, returning
into the main stream, and finding entrance into the Gulf, from which it
had been temporarily detained. Without the bayous the lands adjacent to
the Lower Mississippi would, with very few exceptions, be subject to an
annual overflow, and be perfectly worthless for certain agricultural
purposes. In summer the bayous in numerous instances become perfectly
dry, and give a very singular effect to the appearance of the country.

Below the mouth of the Red River the tributaries of the Mississippi
cease, and the entire volume of the river is attained. As a protection
against serious consequences arising out of such an immense mass of
water, nature has again introduced a remedy. This consists in a number
of lateral branches, which leave the river a short distance below the
mouth of the Red, tending directly to the Gulf, through a continuous
chain of conduits, lakes, and marshes.

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 attai