Weekly national intelligencer. [volume] (Washington [D.C.]) 1841-1869, 1851-08-30
TO THE EDITORS.

BOWLING GREEN, (kr.) AUGUsr 20, 1851.
Messrs GALES & SxAToN In late number Of your pa
per see short piece from Mr. Mrson MERrwErHsR,
laon Foucauls experiment with the pendulum in which
be presents difficulty under which he and many others have
abored in reference the assumption that the pendulum al
ways vbraes in parallel planes This assumption has been
used in all the explanations which hare Of the pheno
in question but have always regarded il false
assumption For is evident that in whatever plane the
pendulum vbrae this plane must always pass through the
perpendicular drawn omhe point Of suspension the earths
surface, and this perpendicular, in its different positions
caused by the revolution Of the earth, always pass
through common point the centre of the earth, taking
into consideration only its durnal motion, is evident that
the planes passing through this pependcular nesect
each other and consequently the above assumption he
Tue have not yet as think, any rational explana-
ton of the phenomenon of the pendulum revolving while it
vbates, though do not presume to suppose it has been
nationally and satisfactorily explained have always thought
that it might be explained upon the principle of the trade
winds. The lower of the atmosphere in passing
ward the EQUATOR in consequence Of the great areacon Of
the air there falls behind the motion of the earth and
relative motion. The upper strata likewise,
in flowing toward the morrill, eastern notion The
Of this is well understood by almost every
need any explanation here. Upon the principles,
Think the revolving of the pendulum may be explained
Suppose pendulum be started to vbrate the plane of the
merdisn In order to remain in this plane it have in
all parts of its Of VIBRATION the eastward motion
which that part of the plane has in which il But tho
southern part Of the Of vbraon being further from the
centre Of motion than the northern part, must if it remain
in the plane of the meridian, have greater motion
than the northern part Hence the pendulum remain
in the plane of the meridian unless in vibrating constantly
change its eastern motion, which, according to the lows of
motion, is impossible. 1t therefore eastern
ton, which is between the extremes Of these notions
and consequently, when arrives the southern part Of s
of vibration, has less velocity than that part Of
the plane of the meridian in which then is and it mani
testify must fall behind In like manner, when arrives
the northern part of its of vibration has velocity
great for that part of the meridian in which it then is and
consequently departs from to the Hence, when il il
in the southern part Of its must depart from the plane
Of the meridian toward the west and when in the northern
part toward the east in accordance with observation.
In investigating this subject fully according the above
principles, have arrived at the following result namely
That the pendulum in vibrating in any direction departs from
that direction which is equal that Of the durna
motion of the earth multiplied by the sine of the latitude Of
the place and the square Of the cosne Of the angle contained
between that direction and the meridian. The process by
which the above result has been obtained cannot be nodu
ed here without the aid Of symbols peculiar to mathematical
investigations. 1t will be from the above that when the
pendulum vibrates from west it has tendency de-
a.e direction and that the true at the equs
tor 10 vibrating in any direction. may be easily cacu
lated also that in the latitude Of forty degrees pendulum
vibrating in the meridian deviaes from it rate which
would make perform revolution in thrtyseven hours and
twenty minutes do know whether these results accord
with experiment. for have detailed account Of expe-
riments made with the pendulum. would be pleased
hear from others on this subject
Respectfully, w. ERREL.