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

letter published in the National Intellgencer' of
the 7th instant making inquiries in regard M FoV
cAULTs experiment. The objection which your correspond
emit makes to the explanation Of the PEN
duum-phenomenon is only ono Of many with which it is
confused. Without discussing these ask leave offer
explanation Of the motion Of the pendulum, which tome
entirely satisfactory and hope that it may be equally clear
and simple your correspondent and others conending
with similar difficulties
All bodies upon the earth subjected power called
the centrifugal foce (poduced by the revolution Of the earth
from west to eas) which tends draw them towards the
west The effect Of this force may be thus Take
plumb line in your hand, allowing the plumb to hang to-
wards the centre of the earth your hand rapidly to-
wards the east and the plumb, nsesd of remaining undr
your hand, will appear ay towards the west When the
pendulum suspended the point Of suspension the
earth revoves from west to and the pendulum, unless
in vibration, will hang beneath the point Of suspension. The
centrifugal force exerng its power the pendulum,
when not in vibration, but il is opposed and parayzed by the
resistance of the air friction, and especially the attraction of
gravity These three hold the pendulum in its place. but if
they could be destroyed the centrifugal force would imne
dately draw the pendulum towards the west
Now, the pendulum in vibration the three oppos-
ing resisting forces in overcome, and the
centrifugal force has opportunity to make itself perceived
Thus let the pendulum be drawn up towards the SOUTH the
attraction of gravity draws it towards the centre of the EARTH
making it take direction north the impetus gained in its
descent carries on, and it begins to ascend AT this
stan when the begun the centrifugal force is per-
ceved. The impetus Of the pendulum the
traction Of gravity, the resistance of the air, and the friction
and the centrifugal force has only contend with the
dency Of bodies to 10 straight lines The pendulum,
them is carried by the centrifugal force little to the Of
north isto be observed that in its first ascent the line in
49,
Of direction in which the centrifugal force draws it, When
the pendulum begins descend again the centrifugal force
loses its power and the pendulum, falling towards the eah
CENTRE goes in direction little the Of south Hav-
ing passed its natural position, (vz pointing the earhs
cene) ascends in direction the of south and
the centrifugal force begins again draw towards the west
but the centrifugal force draws in line forming an
angle with the line Of notion Of its effect is
less than before and hence the pendulum drawn
trely back its first position The pendulum descends
IN direction the west Of north, and, having passed its
tural position, begins its to the west Of north The
centrifugal force draws in line forming obtuse
gle with the line notion and, consequently with increased
power manifest that with every ascension Of the PEN
dulum in souhwardy direction the angle formed by the
line Of notion and the line in which the centrifugal force
opestes becomes and acute and consequently,
the power Of the centrifugal force constantly diminished
whereas with every ascension in nohwardy direction the
angle becomes and obuse and the power of the
centrifugal force is constantly increased.
Thus in the Of few vibrations, the pendulum will
have left its original line of vibration (vz north and SOUTH
and will in line running degree west Of NORTH
and one degree east of south.
The truth Of this explanation may be tried in this way
Draw the pendulum towards the south and let CO. 10 the
of few vibrations will in direction one de-
gree ,Det Of north, and degree east Of SOUTH Draw
the pendulum up towards the north and it will move after
few vibrations in direction degree east Of morrill, and
degree ,Dc of SOUTH Draw up towards either the east
or Oest audit will constantly in direction east and esf
Draw it up degree north Of east, and alter lew VI
braons it will in direction east and '1es but will
attain direction south Of east and north OF 'Oesf
Draw up degree south Of east and il will presently
in direction east and oes but never in adlrecton one
degree north Of east and degree south 81 'oesf.
have never seen the experiment tried, and therefore my
explanation entirely upon theory any one will try
the have suggested, will be glad to see published the
results Of his experiment Practice, believe, will confirm
| the explanation given BY IHEoRf.
Il