Hillsdale Whig standard. (Hillsdale, Mich.) 1846-1851, 1851-05-13

The experiment now being exhibited in
Paris, by which the diurnai ration Of the
earth is rendered palpsble to the senses, 10
certainly one of the most remarkable Of the
modern verifcations Of theory. At the GEN.
ire of the dome of the Pantheon a fine wire
is attached, from which q sphere Of metal.
four or FIVE inches ia diameter, is suspended
so as to hang near the floor Of the building.
This apparatus is put in vibration after the
manner ola pendulum. Under the eonesn-
trcal with it is placed circular table, some
90 feet in diameter, the circumferenss Of
which is divided into degrees, minutes, &c,
and the divisions numbered, Now, II can
be shown by the most elementary principles
of mechanics that. supposing the earth to
have the diurnal motion upon its axis which
is imputed to it. and which explains the phs-
nomena of day ard night, sc, the plan in
which the pendclum vibrates will not be aft
ected by this diurnal motion, but will main
tain strictly the same, direction during twen-
ty-four hours. In this interval, however, the
table over which the pendclum is suspended
will continually change its position in virtue
Of the diurpal motion, SO as to make COM
plete revolution round lis centre. Since,
then. the table thus revolves and the pendu-
lAul HilCu dttS OfCI u uOts AOb f0FViN0s
the consequence is, that a line traced upon
the table by point projecting from the bot
tom Of the ball will change its direction rel
atiyely to the table from minute to minute
and from hour to hour. so that If such point
were pencil, and that paper were spread
upon the table, the course formed by this
pencil during twenty-four hours would form
a system of lines radiating from the centrc
-, ,.Il Al n
the interoal of one hour would always form,
an angle with each other of Is deg, being
the Gath part Of the circumference. Now,
this is rendered acruall visible to the crowds
which daily flock to the Pantheon to witness
this remarkable experiment. Tho practised
eye of correct observer, especially il aided
by proper optical instrument, may actually
see the motion which the table has in COM
mon with the earth under the pendulum be-
tween two successive vibrations. 1t is, in
fact. apparent that the ball, or rather the
point attached to the bo tom oi tho ball does
not return precisely to the same point ofthe
circumference of the table after two success
i've vibrations. Thus is rendered visible the
motion which tho table has in common with
the earth
1t is true that. correctly speaking, the ia-
bio does not turn round by its centre, but
turns round the axis Of the earth; neverthe-
less, the effect of the motion relatively 10 the
pendulum suspended over the centre OF the
table is precisely the same as it would be f
the table moved once in "a hours round its
own centre, for although the table is turned
in common with the surface Of the earth
round the earth's axis. the point Of suspen-
sion of. the pendulum is turned also in the
same time round the same axis, being contin-
ually maintained vertical above the centre of
the table. The plan in which tho pendulum
vibrates does no', however, psrtake of this
motion, and consequently has the appear
ance Of revolving once in "a hours over the
table. while. in reality, it is the table which
revolves once in "a hours under it Lon
don Times.