The patron of husbandry. (Columbus, Miss.) 1875-1883, 1882-05-06
NO. Nv

winch Sapl. EddS COulu get congressional
permission to construct Jetties.
NO. ".
The precise character of the action of
sediment bearing stream, the obstacle to
navigation which is a result of that &C
ton, and the effect which if is sought to
produce by the construction of Tetties, are
matters full understanding of which is
desirable before we proceed to a further
examination of our subject The prin-
ciple upon which this enterprise rests is
the relation between the velocity of cur
rent of water and its capacity of holding
in mechanical suspension the solid mat
ter which it has taken up. This relation
has already been stated, in general
terms, namely, that the capacity of
suspension increases in the ratio of the
square of the velocity of the ST. cam: and
assuming this basis of calculation to be
correct, the deposit of sediment will be
IN the same ratio inversely. By sufficiently
increasing the velocity of the current.
therefore, the deposit may be so far arres-
ted as to prevent the obstruction of the
channel: and this is done by combining
the stream within narrower bounds than
those which nature has formed, until it
reaches such depth of water, in lake or
gulf, that nc accumulation of the deposit
will be appreciate as an impediment to
navigation.
1t is manifest that the obstruction by the
formation and effect of bar such as that at
the mouth ofthe Mississippi must be fatal to
commerce, except by vessels of exceedingly
light draught, and it is equally clear that
if by narrowing the channel above the bar
and thus increasing the rapidity of the
current, the river can be made to hold its
sediment until the mighty depth of the
gulf itself is reached, the force of the cur
rent thus produced will cut channel
through the bar, and the sediment will
at last ind safe and harmless resting
place on the gulf-bed, hundreds Of feet
deep This is the theory of the Jetties
The Mississippi, widening. at its mouth.
Stacking its current as it spreads out, srd
thus losing its power to carry on the sedi-
ment contained in it, has been for centu-
ries depositing its load at its outlet. and
the bar is there as a consequence. The
purpose of the Jetties is to contract its
flow, create swift current and thus as it
were saw channel through the bar. Be-
yond that point, whatever shoaling may
occur must require many years to pro-
duce any visible effect. The application
of the lefty system to the channel of the
Mississippi river at its mouth, with vissv
to securing to the producers of this country
the benefit of this great natural outlet to
the markets of the world, has been regar-
ded not only as a sensational feature in
American engineering, but an expert
ment having no precedents for its gui-
dance or practical guarantee of its success.
This is the light in which hundreds of
thousands of our people have looked upon
this enterprise, while cordially desiring its
triumphant completion, and entertaining
no doubt as fc the substantial benefits to
be derived from it. But this view Of the
lefty system, whether entertained in a
friendly or hostile spirit, is wholly mis-
take. The method adopted in this instance,
is identical in its character, making due
allowance for the peculiar nature of the