The daily crescent. [volume] ([New Orleans, La.]) 1848-1851, 1850-07-24

Hr eALEn a. yoRsnEr. =. NJ. 9. :.


1. Rate Of FakL-From the mouth Of the river
to point 400 miles up its tortuous channel, is a
distance in right line Of only 800 miles It's
length is nearly double the right line distance
For 200 miles above New Orleans, it may, for
practical purposes, be regarded twice the dis
tance OF the right line.
. The mean depth Of the river at high water
mark is not materially different at Natehez. from
Carrollton, though nearly 300 miles apart sec
ton OF the river at Carrolton made at high water
Of 1919 Is l6s $50 square feet and at Vidala Top
posite Natchez,) the section il I67 600 feet The
bottom Of uniform channel 400 miles up. is
about on a level with the bar at the South West
Pass. The rate Of fall is not uniform on the sur
face but decreases in decliv1ty towards the Gulf
giving curve OF inclination (probably paraboicl
to which the Gull level is tangent at the Balize
The mean rate Of decnation is 1-SO inch per mile.
for the first hundred miles, 200 inches the second
hundred, 23O inches for the third and 3J7 fnchez
Tor the fourth hundred miles Above this point
nave no accurate data but am inclined to think that
the rate Is not materially different TO the upper
extreme OF the delta above the mouth cf the Ohio
These data relate TO high water.
/ s. Ihe low water curve Of decliyitv has a mean
descent OF "A inch per mile for the first hundred
miles, and 30, SO, 120 inches for The next conse
cutiye three hundred miles; making tbe totaI An.
ference Of level 2l.1 feet, from point ten miles
above hatcher, to the Balize
A. These rates not uniform for short dis
anees interrupted as the channel is by many short
Dehus Wnlcn arrest the currents regular Hovv and
make series of comparative levels and falls in the
surface current The means Obtained are from
levels made OF segments of the channel. 25 %. Isl
and 100 miles in length, and are, think. reIIable
They are, at least the best data within nv know
ledge -''-
S. Depth Of Water- Within the A00 ,o;l.v
treated the depth of the river at high water i mot
materially different Near Natehez. found an
extreme depth Of 1sS feet, and ike depth has
been found at several points in the vicinity o New
Orleans.
One depth of 1877 feet was recently found mar
Shrewsbury, about ten miles above the civ
These are extreme cases. When the channel ix
distant from both shores, 125 feet IS the usnaI
maximum. section made in front Of YidaIia,
laI 1 a nlle oeiow the Natchez ferry, gave a mean
depth OF sos feet, with maximum OF about I3O-
and like section of high water channel at CARROLL
ton gave mean depth Of II 6 feet The low water
depth may always be obtained by substracting the
range from the high water. At Vidalia the range
Is ol feet and at Carrollton Is feet. The mean
depth of the low water sections would then be
80 feet and 500 feet And the sectional areas al
low water give 1330l0 square feet for Carrollton,
and 5000 at Vidalia
6. The channel continues to maintain n great
depth, down TO point very near the debouehure
how near, know not, but certainly beyond the
head OF the passes. AT Fort jackson it is l36 feet
deep, and point midway down the South West
Pass was found 102 feet
2. Wtdth.-The uniformity of breadth in the
channel is remarkable feature Of the Mississippi
river. great number Of measurements made Nv
myself, from the Balize to Galena, L 700 miles m
the river give mean width, including wide places
IN the bends OF about 1000 yards excluding these
eOO yards; and the upper portion Of this is wider.
including exPanses produced by bends and islands.
tnan loVO yards but excluding them, they are the
same The addition Of the four great rivers below.
make no increase in the breadth Of the river. The
Missouri at Bonneville, 800 miles above its mouth
found half a mile wide
IL appears, from these facts relating to The width
oil the Mississippi, that it does not follow the law OF
connnent streams, as given in the books. We
shall have occasion to see that in many other fea-
lures il is river slti ageaeris
s. Velocity of Csyrenfs.-To obtain the surface
velocity OF the river, | have established parallel
sights, transverse to the river, and with asss-
tant at one OF the stations, timed floating drift
wood. on still days, at all parts of the surface est-
mating by the eye their distance from shore. This
have done at all stages OF water and derived the
mean OF each set, to the number OF many hundreds
OF observations.
g. The result shows mean surface velocity at
high water of 261 miles per hour, at Carrollton,
| and 2.60 miles per hour at Vidala respectively
$50 and 3.S2 feet per second OF time The one
was derived from l76 observations, and the other
from 20 observations. At low water, Carroiiton.
las miles per hour, all feet per second at
Vidalia 134 miles per hour, 225 feet per second
TO- The mean velocity for mean water as derived
from thirty years observation, is 226 miles per
hour, or 295 feet per second.
IL. The velOcltes at various depths are not easils
obtained The irregularities OF bottom and sides
in the channel, and their continually shifting ma
ure, give many lateral and vertical directions to
portions OF the current, very much 10 eoualize
the current velocity, at all depths Besides, the
aIgeness Of the volume renders friction much Iees
influential than is usually computed for iiuents
Accordingly, in sounding, have found the lead.
when thrown in great depths, to be driiIed down
stream, as last as the boat from which it was