Port Tobacco times, and Charles County advertiser. (Port Tobacco, Md.) 1845-1898, 1851-06-25

are given ny french writer's where persons have
been poisoned from eating worm-eaten peas, con-
tanning the maggots and beetles of the Bruchus
Pisi.-Patent Office Report.
THE EARTH'S DIURNAL ROTATION ON
IT'S AXIS RENDERED VISIBLE.
The best and most lucid description we have
seen of the beautiful experiment of FoucAuLr,
which is attracting so much attention in the scien
tifc world, is the following from the Savannah
Republican. 1t demonstrates that the experiment
is as conclusive as it is simple
This experiment is one of the most beautiful,
simple and wonderful of the age in which we live
The sublime mind of Lapace cast about for some
ocular proof (eviden to the senses) of the earths
rotation upon its axis, but did not happen to fall
upon it, 1t has been reserved for another French
man, Foucault, to illustrate it. We published,
few weeks since, an account of his experiment
made in the Pantheon. in Paris. That account
has been the subject of much speculation here as
elsewhere. These investigations have often, we
believe, ended IN incredulity.
The experiment may be thus described Sus-
pend considerable weight by a very fine wire,
say thirty forty feet long, that it may osciate
with perfect freedom. Place underneath this pen
duum table, with graduated circle upon it of
the same diameter as the arc which the pendulum
describes and with its centre exactly beneath that
of the arc. The pendulum will not continue to
vibrate over the same diameter Of that graduated
circle, but will reach points on each side, at
every vibration, completely to traverse the
circle in twenty -four hours. Thus, supposng the
circle to be the common clock dial, graduated
with twelve hours, if the pendulum be started to
vibrate the diameter from VI to XII, two
hours afterwards it will be found vibrating over
the diameter from VII to /.
To make this Ineligible is by no means an easy
task In order to do it let an observer suppose
himself to stand at the North pole of the earth
If the time be summer he will see the sun travel
round the horizon once in twenty-four hours. In
other words, such observer being in the axis
of motion of the earth, while the sun is stationary
is turned quite about, returning always to the
position in which he first, once every "a hours
This is the di,lrna motion of the earth The sun 5
apparent motion is the real motion of such an OBJ
server. Now, suppose this same observer were to
remove from his post, and place there a circular
table some six or ten feet in diameter whose CEN
tire shall be in the axis of the EARTH or right over
the spot where he stood. This table would turn
round, in like manner, once in "a hours, and if
vibrating pendulum could be so supported over it
so not to partake of the motion of the earth and
table,. e., if it could be made to vibrate lover
the centre of the table) as always to keep in the
same direction or plane-then such pendulum
would appear to pass consecutively over every
part of the periphery Of the table once in "a hours
Or, to speak more correctly, the table which has
circular movement with the earth, would present
every portion of its circumference under the pen
duum, which is always supposed to move in the
same rcctilinear direction without reference to
the motion of the earth. Now it is possible to
suspend and cause to vibrate pendulum in the
manner described Therefore it is possible to per-
form the experiment.
When motion is impressed upon pendulum,
causing it to vibrate in certain plane, natural
II f, t1,aro
dulum be suspended by strong iron bar, it will
then constantly change its plane of vibration with
the motion of the earth-i.e., of the point to which
it is fixed above. But this is precisely what it
will not do if it be suspended from delicate silver
copper wire, for then if the pendulum be of the
weight of several pounds, its power of vibration,
or its momentum will be so great as to prevent it
from obeying the tendency of the wire to turn
round with the fixed point from which it is sus-
pended. Or, in other words, the lightness, fexi-
bility and yielding character Of the wire, permit
certain degree of torSion or twisting, so that this
onward and direct movement Of the pendulum is
little disturbed (within certain limits) as though
the pendulum were absolutely independent of the
rotation of the earth.
If our observer be supposed now TO set up his
table and pendulum in the latitude of Savannah,
the same results would be Observation the rela-
tive condition of things is precisely similar. Here
the vertical line passing through the centre of the
earth. It is oblique to it, and the angle of obi
guilty is measured by the difference between 80
deg. and the latitude of this place. But in one
revolution of the earth, any particular point on
the table still describes a complete circle under
the pendulum. 1t is not easy for the mind to
imagine this, but it be thus proved. Take
one round ruler, and incline it in an angle of 80
deg, to represent the elevation of the pole cor
responding to this latitude, Take another ruler
and I'm it firmly against the first at an angle of
say So deg. The round and fiat end of this second
ruler represents our circular table. Now, cause
the first ruler, which represents the axis of the
earth, to revolve carefully itself, always main
tanning the same angle, and it will be seen that
notch made ON the circular end of the other will
pass entirely round and return back to the position
from which it started in one revolution What
we mean is, that this point on the circular end of
the second ruler, will not only revolve round the
first ruler, but that it will have another revo-
luton round the axis of the ruler to which it be-
longs.
Vow if any heavy body be out of contact with
the earth, it does not partake of the circular mo-
ton round its axis. This body in question, how
ever, being suspended from fixed point as above
is impeHed by those two motions which affect the
earth-the one carrying the planet forward in its
annual orbit round the sun, the other that which
causes it to spin round its own axis once day
Hence its motion is a tangential one, and is the
resultant of the two motions above indicated, and
is diagonal with regard to them. The twisting
only once round in twenty four hours of the long
and delicate wire, is force very insignificant
when compared with the vibrating power of a
weight of several pounds. The wire is sufficient
to sustain the weight, but not to communicate to
it that rotary motion to which its point of suspen-
sion is subjected. Though the table below and
the point OF suspension above, and indeed the whole
apparatus, partake Of the motion OF the earth and