Weekly national intelligencer. [volume] (Washington [D.C.]) 1841-1869, 1851-06-14
TO THE EDITORS.

FoUcAULrs theory Of the pendulum, showing the re-
voluon of the earth round its axis to the human eye
lead to two useful resus-one, more distinct view OF the
earth itself as machine the grand scale second the
pendulum smaller machine within the larger and both
moved by the power Universal GrautatiOn. It may
be observed in advance of machines connected and
SO enormously differing power, that the movements Of the
lesser must yield to those Of the larger and therefore,
great result to be hoped for from the experiments making
the Of the penduumha il, the discovery
Of the true theory Of placing that instrument The necess
of such discovery will be obvious from due attention to the
great laws of motion produced by the primary laws, CRAWL
tatioD, and centrifugal force.
In regard such recorded experiments in vercaion Of
Foucaus theory have appeared in the public prints il
cannot be deemed pesunpuous to suggest that they far
from sufficient sustain definite conclusions the
deviations Of the instrument ITSELF The question may
be raised, not these deviaons occasoned by the NAL
placing Of the original Of OSCILLATIONS and the obedience
Of the instrument however placed to the two superior pow
Of gav,aton and centrifugal force The subject de-
mands, and must receive, extent both in time and DIS
lance from each other of location in the places Of observation,
before the becomes Such the in
determining the real form of the earh it's distance from the
and the relative distances Of the other planets Of the solar
system from each other and from the Has any gest
truth been developed in any other than BY long
and fkilful consultation Of the laws Of Nature !.
In fine, before this theory be productive Of scen
ic results It must be carefully and expeimenaly tested
from the equatorial to the borea regions The pendulum is
n ITSELF the only real Of time far the most
simple in construction and important 10 Of all machines
and the interest it has recently excited may lead to
quences not yet suscd but safe conclusions must follow
not precede, observation.
From actual measurement this planet he earh) Is found
be oblate spherod in equatorial diameter miles,
and axis 1899 miles in both diameters, emitting unimpor
tant fractions The earth is therefore, obae spherod
epsod Aattened at the poles In this investigation the
orbit motion may be omitted, having appeciabe effect
on the relations of relative gravtaon Of bodies
face So however, in regard to the motion round the
axis Here the two antagonist principles, attraction and
centrifugal force, into full operation. Attraction,
tending combine every particle into sobuar form round
centre centrifugal force, to throw every particle into space
at right angles from the ar Of rotation The forces,
by their antagonist action, have modified the form Of the
EARTH and have made it epsod in place Of globe, and
maintain il in that FORM The power Of central attraction,
though SO immensely greater than that Of centrifugal force
could no, prevent the latter from having its share in the grand
effect and conclude these remarks BY suggesting the quey
whether or not their antagonist and everdung action does
not regulate the motions of the pendulum
WILLIAM DARBY.
WAsHrssroS, JUSE 10, 1851.