New-York tribune. [volume] (New-York [N.Y.]) 1841-1842, 1841-11-25

which ii may De- considered rash 10 attempt sosa-
ton before popular audience: stil | see no rea-
soR 10 shrink from it and SHALL therefore eaeeavor
70 explain the method by which the Earth has beer
weighed and not only the Earth but every body OF
the Solar System. and even the Sun itself, which
have all been weighed in balances infinitely more
delicate and susceptible otiatniely greater socur-
cv relatively 70 the masses weighed than the incest
scales of the chemist. The method, the spirit OF
which am about 10 explain, was discovered BY the
celebrated Ca,endsh. who has conferred more
honor on the i!lustrious house with which he is
,oo,.c.sd by his scientific discoveries than all its
titled members.
SUPPOSE small ball Of lead be suspended by
s;rin- above the Earth the Eerths attraction
would cause It 20 hang in such direction that the
string would pc.nr 10 it, centre Now suppose l
much larger ball suspended in like manner above
the earth. and At some distance from the smaller
ball: then suppose the Earth IL be removed he
SINAI! ball will have no inclination TO keep It's for
rner position but attracted by the larger bail, II
will rise. and the string will point directly to tue
csatre of the larger globe. Now. suppose beth the
Earth and the large ball 20 retain their position :
the small ball will De subject 10 the attractions OF
bo;a and viii Weld TO neither. but take position
between the two nearest To The Earth, OF course.
because the Earth is imneasurably larger than the
large ball hut still inclined somewhat 10 the latter
Cayendish proceeded in precisely this way
He suspended small! ball very dellcaIely and had
4 much larger one placed near. The small body
Of course changed its position on the approach u
the larger. Cavendish measured the distance 10
which it was drawn and By computing how much
/; was drawn from lis natural position, and how
much it differed from what it would have been
with the ball alone, he readily discovered the pro-
potion the weight of the large ball bore to the
weight of the Earth. He found that the weight
Of the Earth was five and ha.f times great
it would have been had it been composed of water.
Nav cubic mile of water is found to weigh
l,354, 0C0, 600 Of tons. The aggregate weight OF
26S 900 600 of such reservoirs will give the weight
of the Earth. 1t is then upon this weight that at
traction depesds.
But | proceed to speak of the vicissitudss OF
Day and Night. II globe BE- projected into
space at any distance from the Sun. it will depend
upon circumstances how it will ac; to rotation.
Ii the projecting power should strike it directly
6chiad its centre it would not revolvc at; all aud
supposing this to be the case with the Earth, our
DAYS and night. would each have been six months
in length. If the impulse were given aside from
the centre. the body would rotate and the velocity
of its rotation would depend upon the distance
from the line of the centre at which the blow was
given. With these facts every bard-player is
familiar. The slower the velocity the longer would
be our days and rice rersa.
The rapid succession OF day and night would be
attended By another circumstance of Inconvenience
to the inhabitants As the Eurth rolls upon lis
axis II power is produced which operates to throw
from it bodies upon its sur;ace-caled the centri-
fuga force; and indeed il the Earth revolved III %
minutes no body could remain on Us surface. \
ship would be blown b. puff oi wind t,om the
\ motion rapid would balaRce The power OF
gravity, and any impulse would drive the body OF.
All bodies would lose stability if the days and
nights were shortened.
Next let Us turn attention to the Seasons
And in the first place we Deserve that they are
not necessary consequences of the common proper
tie, of matter. Ii the Earth were suspended so
that its axis should be perpendicular 10 the plane
OF its orbit around the Sun, should have no
seasons. 1t nigh. have been so, and indeed there
bodies in which this is actually the case: their
days and nights are of course equal. These are
the chief things noticeable concerning the Earth.
In attempting to prove that the planets the
habtations Of creatures similar to ourselves should
we find on examination that of them have
Day and Night Identical with ours in length; that
the weight of objects their surface is the same
as that oa the Earth shall certainly have strong
evidence of our proposition. Passing to the e1-
animation Of other bodies of the Solar System we
must ascertain whethcr they are subject to the
physical conditions which confer qualities upon
our Earth So well adapted to the welbeing OF
man.
lst. What are their distances from the Earth,
and how are they ascertained 1t is scarcely
So, c,I l.,
PLANTATION of the method of calculating the dis
tances. The angle -ubtendcd at the planet by the
Enrth's diameter is to be measured by an instru-
ment: after which the operation is u simple opcr-
alton in irigonomery.
ID. The masnitudes of the planets are Galctl-
lated by u similar process Fhe angle subtendc
at the Earth by the planets diameter may be
measured with quadrant after which the ques
ton becomes simple trignomettical problem.
Sd How the bodies of the Solar system
weighed We appeal in this case las often in
science) almost to ,he plaything of child for the
origin OF our calculations. II ball attached to
string be swiftly whirled in circle, the motion
gives certain force tension to the string, and
the force ausments with the velocity and the dis
lance OF the ball from the centre. This is strictly
the result OF experiment. Apply the principle TO
the planetary bodies. The Moon revoye. about
the earth in % days; its velocity therefore easily
ascertained. It's distance from the centre OF rota-
ton is 30 600 miles. The power of gravity
serves the purpose OF string, and thus we are
enabled to calculate the force excrted by the Moon
against gravity-or in other words its reigM.
We find that the Sun exerts on each of the pla-
nets an attraction equal to $40, 900 times tina,
which the Earth would exert if placed where the
Sun Is. The inference is that the weight of the
Sun is 100000 that Of the Earth Thus we weigh
the Sun and all the other bodies of the Solar Sys-
ten, with the following results: Surprising the
weight OF the Ear,h to be l that Of Mercury would
be l-6, Venus 1920, Mars 10, Jupiter 300, Sa-
turn 100, Herschell II. sss-ss