The Donaldsonville chief. [volume] (Donaldsonville, La.) 1871-current, 1882-09-02

many feet deeper would the channel have
to be to carry off. within leyees, the waters
which yearly food tlle whole distance
outside the lcvees to a deptl, Of from five
ia fifteen feet and width Of miles upon
miles And what guarantee have we
that because the ietties have deepened
the water x feet iii IL distance of X
| feet that therefore the river, if walled
up as it is at the jetties, would deepen
its bed in proportion AAa distance Of one
thousand miless Ey the levees be
raised and the jetties placed everywhere,
yet, if the velocity of lightning itself is
not impaired to the current, sediments
will subside all along the way. I pre-
sumo it would be impossible to prevent
the earth, pebbles, mud, etc, which are
held in suspension, from settling, because
the all-controlling law Of grayitation
| will attract them to the bottom Of the
river. Now, within as small a space az
the jetties, the sediments are sensibIy
secured ont by the apcentration Of the
current. Capillary attraction is likewise
1 perceiyable in small tubes and not iii
large surfaces. Again, a sufficient force
is speedily found to raise water to a GER
| tain height, say 80 or "a feet, but what
| increase of power, with the same ma
cbinery, will lift it higher7 just like a
vacuum, which can easily enough he Gre
ated, but to secure perfect vacuum Is
another thing. The wings Of d humming
bird will destroy the uis inertia, but what
| effort on earth could continue the motion
to perpetuityy There iy|a limit to every
thing. Then it may be conceded that
ietties will clear their channels within
certain distances, but that the system
could be carried ont successfully ad it,
Jinitam is problematical.
| Now, per contra: ii water he poured
into a funnel faster than it can run out
at its oriiGe, it will flow over its sides ;
and if the mouth of the river il not wide
or deep enough to discharge the water
which flows to it from a hundred streams,
! will it not run over the leveess Can any
| one doubt the fact that the more open
ings are made, tapping river, The more
water they will draw from it, and the
more. the surface level will be lowered
Depletion will certainly reduce volume.
Even DR.. Sangrado with all his quackery
undertook to hasten insufficient perspira-
ton by copious bleedings. The Egyp-
tians practiced the outlet system to such
an extent by lakes and canals that out
OF foundations of the Nile Of some twenty
five feet in height, scarcely e-tenth of
the water which poured from Abyssinia
and Ethiopia reached the sea. But it is
| cnntenled that outlets deaden the cur
rent and cause deposits which fill and
elevate the beds of rivers. This is true
to a certain extent, just as. it true that
jetties, to a certain extent, will hasten
currents and deepen channels. Had the
bed of the Nile been elevated since the
outlet system has been inaugurated there
it would now be mountain; whereas,
we have no evidence that the channel OF
| that river is much different than what it
was in the days of King Menes; grandson
of Noah.
We know that every inequality, bend
or angle in the path of running water
| will retard it and cause deposits if it be
charged with Impurities. When the
course is smooth and straight water will
flow evenly and drop it's sedilnentary
matter uniformly. So, consequently,
when au outlet is practiced there is u
general rush of water to the orifice,
which creates cross or opposing currents,
and these retardations cause deposits ;
but these accumulatiuns could in great
measure be reduced by Il proper construc-
ton Of the openings.
| Let us suppose that Bonnet Carrie, La
fourche, Plaquemine, etc, etc, be we'll
leveed and scientifically prepared to serve
as conduits to the overburdened Missis-
sippi; that where the river flows into
| them, sufficient locks he constructed, and
at their mouths jetties, il necessary, be
established; that when the river rises to
dangerous height these outlets be
opened; that when the river falls they
be closed to avoid further deposits
| would not the bayous and ereyasse chan
| nels carry off q vast volume of water
from the main artery And could not
.jetties come into play, if constructed
near the outlets to sweep away whatever
deposits these last may have occasioned 2
As I said, are they antagonistic Be
cause one causes deposits and the other
sweeps them away, can they not be made
to combine and TO neutralize each other