The Cairo bulletin. [volume] (Cairo, Ill.) 1872-1878, 1878-02-01

twice as great as the other, bnt the
larger Pipe will holi tour iimesShe guar.
tIty OF water per loot OF as length, ana
consequently, IL the two pipes have the
same slope, the water will run most
freely through the larger one, because
the water In 10 has only half the friction
to retard II. SO, IN produce an equal We"
loclty In both pipes, we must give the
smaller one sleeper slope. THIS Is
precisely what the river does. where
its grand volume is divided by Islands,
or expanded with great wi Iths, the
friction OF the bed is Increased, sluggish
current onsues, deposits are thrown down
unit! the bed is closed, and If two inches
per mile be not slope enough. the de-
hosting process continues until three
inches ur four, or all that Is needed, is
obtained. For. mark you. the river must
have certain rate OF current. II VIII
have n. and no man need waste his time
in. dcvlsing schemes 10 prevent it,
CERTAIN RATE or CURRENT
Is necessary Tor lts very existence. as
You will presently ser; Tor Its tributaries
are usually pouring into its bed thrir
burdens OF sediment, and 1t must dis
charAe this mad and sand into the sea,
or its own channels will become chokcd
up. And 1t Ia equally impossible tor IT
that the current be not too great, for IL
would then have It's alluvial bed cut out,
enlarged and uriittpd Tor the purpose for
which nature designed It.
We shall sec that the Creator has, IN
m, ,.,icnnpl anlnyVpI tho
grand old river with almost scntient
tucultjcs for it2 nrs.orrsiinn, BY these
IL is enabled TO change, abandon or alter
its devious channels, and elevate or lower
its surface slopes, and also temper the
force which impels ito floods TO the sea
that It's current may be regulated, Sc
cording TO It's needs are modified, ~ the
cver.changing conditions with which 1t
is surrounded.
THE sEIP.RE6uLATIoS or THB CURRENT
Is accomplished by the power which
nature gives 10 its flowing water, 70
transport sand and earthly matters sus.
pended In It's volume. The river water
is consequently charged with this solid
matter, and lis power 10 transport II
depends wholly upon its velocity.
This Is, perhaps, the most essential
truth underlying the plan OF improve
ment propose, and | want you to par.
ucularly note ii. for IL Is boldly and
Professionally denied BY the Humphreys
and Abbott ana the army engineers who
opposed the jettlss al the mouth OF the
Mississippi, Ny convictions and theirs
arc diametricaily opposed upon this
proposition, namely, that the quantity OF
sediment carried In suspension by the
rivers to the sea depends upon tie veloc.
Ity of thc current. That is, that the
quantity increases and diminishcs with
The velocity OF the current. the ratio OF
quantity TO velocity is, however, inodi-
tied by the depth. That is 10 say, the
quantity OF sediment Increases iess rap
idly with an increase OF current In deep
water than ii does In shoal water.
Here Is a plain, simple proposition,
that the elevation between the quantity
OF sediment suspended and the rate 'bt
current is An Intimate and direct one.
II ! am wrong. the system Am p.opos.
ing is utterly worthless, and e.
THE OUTLET THEORY
OF the levee commission, SO emphaticslly
lndVFsed by the chief VI engineers Is cor
rect. Ii viii be seen, theH, that the plan
OF Improvement put before tho country
by tho army engineers, and the one
propose, rest upon totally different u.s.
sutDptions regarding fundamental
physical lsct, and, therefore. our plaus
are totally different. Mioe is based
upln the concentration and coDserva-
ton OF TIE river volume; theirs,
upon the theory that Its diffusion
BY outlets will lower tho i,ood>liue; that
changes in The velocity oil the current DC
in Us bed anu That ,iess9lhmg" tG&v d fiaiiSgg
flowing through ne bed, VIII not iessen
the channel nor steepen its slope. They
declare that the results OF long and care.
fully conducted experiments al Columbus
and CarrUlton, TO determine tbs very
question OF relation between velocity of
current and quantity Of sediment utterly
disproyes the existence OF any such re
fition. Ny hopes OF success at the jettes
were based upon the TACT that 1t does
exist. as have stat, d, and that the
slightest check in the current will causc a
deposit OF sediment.
THE PERNICIOus ERROR
was advanced by Nessrs. Humphreys
aud Abbot in their survey report, seven-
teen years ago, and was reiterated by the
chief OF engineers during the pending OF
the jeity act. After It's passage II was
officially republiehed by him.
More recently it has been again re,
nh In L.. AIif nf
phreys' and Abbot's. report, with new
arguments 10 support II. / therefore
take This occasion TO cay that tables OF
results OF Columbus and Carr0ltOn eX-
| periments as published in Humphrey
| AMI Abbott's report, do not sustain their
statement, but DO prove the proposition
have advanced, and | hold myseli
resoy to prove before any committee OF
! congress, or any competent scientific
authority, or in the presence of either OF
them, that they have misinterpreted
their own data, and have thus been led
into tho publication VI grave scientific
error.
This Is a purely scientific question. but
one OF great moment In the problem We
are discussing, and think eau make
you understand the error which these
gentlemen have committed by
| A SIMPLE ILLUSTRATION.
The grain trade in 81. Louis has made
most ooyou familiar will, the elevators
which handle II, and you have doubles:
! seen the little tin buckets attached to thu
vertical belt which travels around pull
ley at the top oil the elevator, ami il
which buckets the grain is carried up.
ward. Suppose an engineer gravely tolL
you that there was no relation belwcer
the velocity of the belt or the power 81
the engine driving the belt, and The
quantity or weight oi grain raised BY it
such statement would ba no kss con
trarY TO well established physical laws
than the error ain alluding TO. Bal
suppose the engineer relters,cs his asser.
ton. and declares that 'long.continu.r
investigation on his part proves the fact
You would still dlsbelleYe a statement Sc
CONTRARY TO COMMON s.SsK AND DAHL,