Burlington hawk-eye. [volume] (Burlington, Iowa) 1845-185?, 1851-05-15

THE RorArIoN OF THE EARTH MADE
Misunderstanding to the London
A,heneum, the experimen, now being ex-
hibit.d in Paris, by which the diurnai ro-
tation Of the earth is rendered palpable to
the senses, is one Of the most remarkable
Of the modern verifications oftheory. At
the centre Of the dome of the Pantheon a
fine wire is attached, from which sphere
! OF metal, four or FIVE inche. in diameter,
is suspended SD as TO hang near the floor
Of the building. This apparatus Is put in
vibration after the manner Of u pendulum.
Under and concen,rical with il il placed
a circular table, some 20 ieet in diameter,
the circumference Of which is divided into
degrees, minutes, &c., and the divisions
numbered. The mode in which the fac,
Of the earth's rotation is established, is
thu. beautifully arrived at:
Now, il can be shown by the most ele-
mentary principles Of mechanics that, sup
posing the earth 10 have the diurnal no.
lion upon its axis which is imputed TO il,
and which explains the penomena Of day
and night, &c., the plane in whic., this
pendulum vi5rates will not be affected by
this diurnal motion, but will maintain
strictly the same direction during TWEEN
ty-four hours. In this interval, however,
the table over which the pendulum is sus-
pended will continually change its posi-
tion in virtue Of the diurnai motion, SO as
TO make a complete revolution round its
centre. Since then, the table thus re-
wolves and the pendulum which vibrates
over it does not revolve, the consequence
is, that a line traced upon the table BY a
point projecting from the bottom OF the
ball will change its direction relatively 10
the table from minute to minute, and from
,, hour to hour, 50 that If such point were a
pencil and paper were spread upon
the table, the course formed BY this pen
Gil during "a hours would form a system
of lines radiating from the centre Of the
table, and the two lines formed after the
interval OF one hour would always form
an angle with each other Of Is deg. being
the oath part Of the circumference.
All this. we are assured by the Lon.
don Athen@um, i. rendered actually vis-
ible to the crowds which daily flock to the
Pantheon to witness the remarkable ex-
reriuent. The prsctised eye Of correc,
observer, especially il aided by proper
optical instrument, may actually see the
motion which the tsble has in common
with the earth under the pendulum, be.
tween two successive vibrations. 1t is
in fact, apparent that the ball, or rather The
poin, attached to the bottom of the ball
does not return precisely Ia the same pcin,
Of the circumference Of the table after two
successive vibrations. Thus is rendered
visible the motion which the table has ir
common with the earth.
l, is true that, correctly speaking, The
table does not turn round Ivy its centre, bu
turns round the axis OF the earth; never.
theless the effects Of the motion relatively
to the pendulum suspended over the cen.
tire ofthe table is precisely the same as il
would be is the table moved once in "a
hours round its own centre, for although
the table be turned in common with thu
surface Of the earth round the earth's AK
is, the point Of suspension Of the pendu
lum is turned also in the same time roun,
the same axis, being continually maintain
ed vertical above the centre Of the table
The plane in which the pendulum vibrate
does not, however, partake Of this mo!io1
and consequently has the appearance q
revolving once in "a hours over the tabl
while, in reality. It is the table which re-
wolves once in "a hours under it.
| No more beautiful scientific experimen
has been exhibited: and it is naturally ex
citing quite sensation in Paris.
External gentility is frequently used t
disguise internal vulgarity.