Richmond enquirer. [volume] (Richmond, Va.) 1815-1867, 1831-03-31
ABRIDGENfENT

POLITICAL ECONOMIST
ABRIDGEMENT
Of the Article" Rirers'' in the Encyclopedia Brit.
fdniea. Bell and Bracyute's Edin Edit 1877:
oorant how in these dolly recurring how oeu
oS,nsr osee sy ~" s Snd heavy oxPence @
useless but fequcay hur,ul-Enc'y Brit.
The hrst paragraph relates to the importance of the
doctrine Of the motion OF rivers. Ii forcibly con.
cludes' We must keep up their waters for the pur.
poses OF Navigation or supply their places by canals
we must drain our ens and defend them when drain
cd We must understand their motions and their mode
oil secret sure but unceasng action that our bridges
our whars, dkes, may not become heaps of ruins
The cases Of Italy. Holland, and Flanders are then
cited such has been the experience OF other coun-
ries'" Considerable progress i'm the science might
have been expected and that the Engineer
would be daily acting from established principle and
be seldom disappointed in his expectations. Unforu-
nately the reverse OF this is nearly the rte state of the
case Each Engineer is obliged TO collect the greatest
part of his knowledge from his own experience, and
by many Thought lessons to direct his future ope-
rations in which he still proceeds with he station and
anxiety for, we have not yet acquired principles of
theory, and experiments have not yet been collected
and published, by which an empirical practice might
Hydraulics adds the Encyclopedia, are still a new
study. The mathematician has entertained himself
with elegant applications of Calculus-this is merely
from want OF knowledge of facts. To possess this is
seldom his lot lie is confined to Geometry i'm its alb
stracted form. Here his progress is owing 10 the
intellectual simplicity of his subject. Bnu when we
turn our attention to material objects; without know.
ing either the size and shape OF the elementary par
cies the Lds which Nature has prescribed Tor their
action, presume to foresee their effects calculate their
exertions, direct their actions what must be the con-
sequences Nature shows her independence with
spect to our notions; and, otc0ys faithful to the Lacs
which are enoned and Of ,ohich are ignorant she
never fails to hwar pe,cs disconcert our projects
and render useless all our efforts.
'To wish to know the nature Of the eleme nts il vain
and our gross organs insufficient for the study To
suppose mat we do not know and to fancy shapes
and SIZES at will This is TO raise phanioms aud
viii produce system, but, will not prove foun.
Dalton. Tor any science. But to interroga.e nature
herself; study the laws which che s., faithfully OBJ.
serve' catch her, as we say, ia the fact, ard thus
wrest from her the secret this is the only way TO be.
come her master, and is the only procedure conss
tent with good sense"
"The Iabours Of Keplar, GaIlieo, Paschal and New.
ton, soon become bodies OF sound doctrine Their de-
ducons fair cf the phenomena O,
nature. Whenever man has discovered ga law of
nature he has laid the foundatir n of new science:
ana he has given us new means Of subjAc,ing our
service, some element hitherto pendent and (but
so long as groups Of natural oper atoms follow a route
which appears 10 within sical and will not adm our
calculations we may be assured that zoe are ignorant
OF the principle which connects them all and regu
iatss their procedure.
"Thisis remarkably the case with several pheno.
nena in the motions Of fluids and particularly 10 the
mot on Of water in a bed or conduit of any kind AL
though, the first geniuses Of Europe, have, for this
century past, turned much of their attention TO this
su ject, ara almost ignorant OF the general la,ps
tha' may be ob'erved in their motions We have been
aoie 10 select very lew points OF resemblance and
every case remains ne'rly individual. About $50
years ago, we discovered, by experience onlv the
quantity and velocity OF water issuing from a small
orhce; and after much Idbour have extended this to
any orihcr; and this is almost the tohole Of our conf
DENTAL Knowledge. But. TO the uniform course OF
the streams which water the face Of the EARTH and the
maxim which viii certainly regulate this to our
Wishes W. are, in manner. totally ignorant. Who
can pretend 10 say what is the velocity of river
OF which you tell him the breadth, the depth,
andf haI elixriIx
produced in different parts of a course, T. ~ a Dam
or Weir, IF giuen dimensions, be made in it, or a
Bridget ro,cn across IL? Or, how much its waters
will be raissd by turning another stream into H. n
sunk, by taking of branch 10 i've Mill? Who can
cay what form will cause prevent the undermining
OF banks, the forming Of elbows, the pooling of The
bed or, the deposition of saads Yet these are the
most important questions.
"Tbe cau'es OF this ignorance are the want or I'm.
certainty Of principle; the faiSiiy Of our only
theory, which is belied by our experience and the
small number OF proper ob'srve,ions or exp'rmen ts
and the difficulty of making such shall be seryicea
BILE We have, il is tue. made few experims mt. on
the eihux OF water firm small or6ces; and, from
them we have deduced sort Of theory dependant nm
the fall Of heavy bodies, and the laws of bydrosatic
pressure. Hydros'a'ics is indeed, founded on very
simrle principles, which give very good account of
the laws OF the que'cen, equilibrium of fluids in con
sequence Of gravity and perfect Gudty But by
what rain OF reasoning, can connect these which
(wiih) the phen of the uniform motion Of the
wafer OF river, open etfeam which can derive is
notifications of this mott its velocity. only from
The width or depth ef the stream. These are
the only circumstances which can Distinguish a
portion OF the river, from vessel of The same
size and shape-in which. how.ver the water
is arrest In BOTH gravity the cole cause Of pres-
sure and OF motion but, there must be come circum
stance peculiar 10 runriOg waters, which modifes The
fxeriion Of this active principle ard which, tphen
dsc0rered, must be the basis of hydraulics and ms,
oblige us to reject every theory, founded on ancied
hyPohe'es, and which only lead to absurd concIu
soDa; and, surely absurd conse ences when legti
mstelY drawn, are complete evidencies OF inproper
princp'es'
from orifces, at various dephs we're as their square
roofs; and the fact being verified bv experim emit this
principle was mmsdidely, and ,Ditboui notification
applied to every motion OF water Marico,te Vartg. |
mn, and GnglIelm made il the basis of system of
hydraulic, which prevails 10 this day, with some A.
mendmen,s and icaions."-Tbe Encyclopsdia
then gives 'rspcucus expression of the realoniny of
Cuglismi, Ia his fundamental iheorems Then are
added The consequences deduced, and End il mr.
nouneed, that all these consequences arc confTnry
TO all experience"
alt IL surptizirg,'' Gays the ENcyclsn media chat
tbeory really founded in cooceit, and which in every
most familiar and obvious circunstance il contra
by facts, should have met with 90 much a,tsn,io-
That Varenon should Immediately catch at the notion
Of Gu .lielmi and make il the suhi,ot of MANY elsbo
rate analytical mors, not 10 be wondered a. Ths
author only wanted donner PRISE du calcm: and IL
was usual joke among the AcadeDieans of P,,is |
when any new thsoran, was invented dounoos IL :, |
pdrignon generoIiser. But his numerous, ,beo. |
rems and rorrollaries adopted BY ALL and stiU
makes the Substance Of the present system of Hydra
lies"
Next succeeds full detail Of the opinion Of ,bsss
Ma'hrmalcans, Sir Isaac New'on's observations and
conclusions, and an sverment that an exact owledes