Vicksburg weekly herald. (Vicksburg, Miss.) 1868-1883, 1877-11-30

their PRACTICAL accomplishments 10 the
many and ~stupendOus works OF art
which, to-day, altes. The capacity oil
man 10 grapple with the mightiest Of
physical forces and render them cub.
servlent TO his comfort aud bis welfare.
There can be no doubt that the various
phenomena Of the Mississippi river can
be subjected 10 accurate calculation
with almost the same nicely as the run
ming Of wsteF in a pipe, were the re.
quisite data obtained. There 10, how.
ever, already al hand = suficieDcy Of
data 10 indicate 3 plan Of protection,
aud thus justify immediate operations,
looking to its contamination which will
be more perfectly realized as the char.
scterisIics of the main stream and lie
tributaries arc developed by a we'll Or
gained, continuous aud comprehensive
survey.
This at once supports the inquiry as
10 the nature aud comprehensive esq
OF the colltc,.I ioia. II may DO an.
swered that meteorological observa.
lions, extending ovcr a number OF
years, aud the locality Of such observa.
lions restricted in u own ouu
try, only by the l%atitudinal and
longitudinal points which mark
its widely separated borders,
give Us the average rain fall. Geolog.
ical research has been richly rewarded,
aud National, State, county, corporate,
and individual enterprise have accu'
rA,ely determined the topography Of
40 incoDsiderablG area Of tho conli'
nent. Tue hydraulic theories Of the
Old World have been Investigated
with reference to Tho Mississippi aud
it's tributaries. The river has been
measured from its source to lis mouth (;
its c~ross.sectionsl features have been
determined at all water stages, as also
its high aud low water slopes; lis daily
discharges have been computed; the
amount Of lie sedimentsry matter has
been estimated iis current velocity,
due 10 depth and slope, has been prac'
ticalIy Appropriated, and much is
known of tho reservoir capacity Of the
swamps. From these facts, and others
that arc collateral, we obtain an APP
pr, ximaie ratio between tho surface
Elevation aud tho volume Of extra
nont. In other words, II has been ap.
proximslely determined what will be
the increased height of food due 10
any given increase in the volume dis
charged, when the general dimensions
aud slope of the river are given.
1t is admitted that II that portion o.
tho Mississippi food which lie absorbed
in filing up the swamps, were entirely
excluded from the swamps by q Oys
, tenn Of substantial levees, and forced
f into the channel, there would be a sur
face elevation of one foot, correspond
ing TO an increase Of 5000 cubic fee
Of water 30 included between tht
levees. The calculation assumeI
the average width and depth u
he, in feet, respectively $500 and lis
, The ordinary period Of thigh water ma,
. be assumed to be sixty days. TIL
Swamp lands Of the delta are suppose
10 cover about 10000 square miles
Il those above the mouth OF Red rive
q about 26. QUO square m!Ies. tits though
!, that Eve feet is about a fair average &c
a depth Of inu Idalion, distributed ov'
n the total area north OF Red river, whiC
lie subjec; to overflow. II II be b
!. sumed that the water over the who
OF this area is excluded from Il
10 Swamps by y permanent system
nI levees, we shall have for tho addition
e. volume which, 5y that process, will
III forced into the river, aud which muI
he therefore, DO carried of by the cham,
80 8 GA 1872 100000 cubic ieet. This a
e. ditional volume must DO dIschSrgI
"a through the channel Of the river in 4
es ordinary period oil high water, viii
,b has been assumed to be sixty days. I
increased di ,charge through the cha
10 mel due 10 this cause will then be g
be 403 200 900 cubic feet per diem, n
,ly consequently 500, Ito cubic feet ?
second, kept up for a period of six
&C. consecutive days. II Is then 10 be co
ny ,idered il that portion Of the Miss
I'm sippi foods which is absorbed in ii
ms ing up the swainps, were entirely
Ia. cluded from them by 4 81 stem u! 81
IA sianriAl levees, and forced into
I'D Channe.-wLere an increase OF 3j.C
re. cubic feet pr second will cat
Is an increased elevation of surf,
Of of one foot-the 100000 cuI
Ii, E.at Vap ao.,nuI % awrlnhad wnt