The daily Cairo bulletin. (Cairo, Ill.) 1878-1???, 1883-03-21
THE SUBJUGATION OF THE MIS-.
SISSIPPI.
BY ROBERT .. TAYLOR.
CHAPTER III.


The problem of the rivers improvement
comprehends, therefore, in its broadest
sense, these two requisites-a high-water
channel capacous enough to contain its
floods, and low-water channel narrow
enough to afford the depth necessary for
navigation. And the more nearly indenti-
cal in location these can be made, the more
permanent and perfect will be the improve
ment attained.
In the consideration of any plan for the
accomplishment OF these ends, it is to be
remembered that there are very rigid limits
to the possibilities of engineering methods
applicable to the case. To build upon a
foundation of bottomless alluvium any
break-water or training.wall Of stone or
timber, that shall Withstand the floods that
pour down from the north like an ocean
let loose, is impossible, To dig and keep
open a channel for river that filings down
in its own pathway q sand-bar mile
square as though it were handful of
ashes, is equally impossible. Hence, if at
any point deeper channel is needed, the
river must be coaxed to build it. Its
own Titanic hands are the only instru.
ments equal TO either task
If any one will set tumblerfu of the
coffee-coored water Of the Mississippi
where it will remain undisturbed for TWEEN
ty-four hours, be will find, at the end Of
that time, teaspoonful Of mud in the bot
tom of the tumbler, while the water will be
comparatively clear. If he had kept the
water in motion all the time he would have
found it as turbid as when he took it from
the river, and no deposit at the bottom. In
this tiny experiment is illustrated the most
important law of the Mississippi Rivers
life, viz that the power of water to sustain
and transport sediment depends upon its
motion. The exact relation between the
velocity OF moving water and its silt.csrry-
ing powder is not sscertsined. 1t varies
with the size and specific gravity of the
PARTICLES. But enough is known to warrant
the general statement that every diminu-
ton Of the velocity of running stream
diminishes its siIt-transportlng capacity. 1t
is not necessary, III order to produce this
result, that there shall be cessation of
motion in the water; diminution of its
rate is sufficient.
The operation of this law is universal and |
inyariable, an the largest scale and on the |
smallest The miniature torrent that |
sweeps down the plowed furrow in hill
side field scours its bed clean as long as it |
its headlong velocity. But
when it slackens its course at the foot of |
the slope, it throws down it's load Of sand
and loan in an instant. The delta which |
forms at the mouth of every sediment-bear-
ing river is the same phenomenon on a
larger SCALE
Upon the Mississippi River the traveller
is never for a moment out Of sight of visi.
bic evidence of the operation Of this law.
The following examples will be familiar to
any one who has been upon it. In the outer
curve of every bend, where the current is
swift and strong, the chsnne! is deep and
clean. On the inner side of the return
curve there is slack water and bar. Wher-
ever the channel is narrow and deep, there
is high velocity and no deposit of sedi.
ment Where it is excessively broad and
shallow, bars accumulate rapidly.