New-York daily tribune. [volume] (New-York [N.Y.]) 1842-1866, 1847-12-06

observations were made upon the Moon. at y ably
lon ? $50 wears before the Christian Era And
these observations upon the taking OF that city by
Alexander were said 10 have been presented 70
Aristotle The truth Of this We cannot know but
ore thing we do know-that on the 10Th OF March,
2567 wears ego. there was an eclipse OF the Sun
observed and recorded in the tower erected in that
mighty city; on the sth Of March in the following
year there wes another and on the 4th OF Septem-
Der ia the next year there was another. Aud We
know and understand the peculiarites belonging
70 these antique observations
These are, perhaps among the earliest observa
tions-and Of such Importance are they in linking
the Past With the Present, that but for them we
would az this time be comparatively ignorant OF the
movements Of that wondrOus orb, which does more
for the civilization of the world than any other one
thing Of which we have knowledge. | pronounce
this to be true without hesitation. II 1t were pos
sbe. now totrace with perfect precision the exact
position Of the Moon, we should accomplish more
for Commerce for Science, for Civilization than could
be done in any other way. Why Because then
the tempesttOssed mariner upon any ocean-over
whom days and weeks had passed without bis see
ing the Sun or stars-the moment this silver orb
made its appearance again in the heavens. would
be able with perfect confidence to exclsim: 81
know exactly in what part Of the globe am sltua-
ted the smallest observation gives me my latitude
and the position OF the Moon my longitude. Hence
say it is OF the utmost consequence that we should
with those now making, we are able to approx
mate to the accomplishment Of this grand design
more fully.
But as we come down through the tide Of Time,
we find particular theory adopted with regard TO
the whole system with which we are united-the
old Greek theory, 10 which will just advert 1t
located the + arth in the center, and made the Moor
the nearest object, and the Sun next NOW 1t hap
pened curiously enough that there was one truth
in the theory the Moon did revolye about the
Earth
When Coperncus presented his theory and trans
ferred the fixed center 10 the Sun, causing the plan
cts to take proper positions, rescuing the Earth
from its false position and sending itreyolying round
the Sun the question was, What is TO be done with
the Moon There seemed 10 be a difficulty here.
The query was Is the Moon plan ct like the rest
Perhaps many OF my audience have not thought oil
this. How many OF us have asked the question
How do we know that the Moon reyOlves = Be
cause the books tell us so We are generally In
the habit Of receiving facts AZ that way. do not
remember ever to have seen an explanation OF this
in any book. But Coperncus reasoned in this way.
Said he ] do not believe the Moon revolyes IN an
orbit interior 10 the Earths, because i lind that
evinces a mrcle the Moon in that case should
never leave the Sun butte a limited distance. Now
the Moon does leave the Sun and moves of TIL 1t
is directly opposite and then comes around again
up TO the Sun. | therefore say II does not reyoye
interior 20 the Earths orbit In the next place, II
does not revove exterior TO the Earths orbit; for
find the motion of all the planets exterior to the
Earth. ut certain points of their career becomes
slow-it is arrested-they stop-retrograde-the
stop again, and then take up their onward motion.
Now / understand why it is that We being on the
surface Of circular globe must have these changes
exhibited to us But the Moon never stops and re-
trogrades-iti is ever moving onward, and therefore
is not exterior to the orbit of the Earth.
Here was a farthe: absolute demonstration. IL
could not be either interior or exterlor-thereiore
il was no pianet at ALL Now the phenomena ex-
hibted by the moon were perfectly accounted Tor
I-upon the hypothesist that you make the Earth Its
center-it revolves about the Earth, 1t is our
satellite, ever accompanying us III all our move
ments.
But we come down still farther in the history Of
our neighbor When Kepler discovered the two
laws of planetary movements-that they revoived
in orbits not exactly circular bat little elongated
eiptcal as they are called when, in like manner,
he had discovered, by tracing them up, that a
line drawn from the Sun to any OF the plan
cts always swept over equal areas OF space
in equal tmes--and when, at the end OF
seventeen long years of toll he had also discovered
his last great law, which linked all these isolated
planets into one grand unit, making the Sun always
the center it seemed that nothing more remained
10 be DONE But Immediately the question arose;
What holds these mighty globes steady w nat
power reaches out to them and prevents them from
breaking from their orbits and wandering away
into the blackness of darkness The resolution OF
this probem W as reserved for the immortal Newton
Kepler himself gathered some faint glimmerlngs OF
the great cause that there wasa power OF attrac-
ton existing ia bodies, mutually operating upon
each other but he did not attain 10 the demonstra-
ton of this fact This reserved for that great
man 10 whom we owe our knowledge OF the laws
OF attraction.
Here. If you will allow me. will attempt to ex
plain the mannerin which Newton conducted the ar
,icl, iet To he
fdent that although there are many here who have
given comparatively little attention ~ Astfonoml-
cal Science they will be able 10 follow me readily
in this explanation. Newton began where hepler
left of The latter announced that bodies were at
trscted TO each other, and by force which he be-
lieved decreased according TO certain liked law
and it was to prove this that Newton made his IN
vesticatons In the first place, he announced this
as a law, according 10 his belief: That every body
attracts every other body by force which varies
invcrsely as the square OF the distance III a BODY
be located at distance one the force oi It's aitrac
ton we will call one, Now remove this body as
far again to distance ttcO, and the attractive
power will be one fOurfh-at distance three one
ninth and at distance four 0He-sirteeHth and
YOU can carry out the law to any distance
Now 10 prove the truth Of this law Was the qqss-
ton. In the first place. It is manifest that, whatever
be the law of attraction it will be clearly and posi-
lively determined by the amount OF velocity It Is
capable of impressng upon falling body. This is
Ineligible to ALL II from this point let tall any
object toward the Earth surface under the iniiu
ence Of the force OF attraction suppose tie sixteen
feet in the first second OF time-this sixteen feet
will measure the force of attraction at the Earth
surface Ii itwere possible to 60 1000 miles high,
and from that point, remote IRON the surface OF
the Earth as my first station at the surface vas DIS
taut from the center. and then drop body, meas
ure the space through which It tails, and md II
10 be one'fourth OF sixteen feet IN second, this
would be proof that the law was true But sup.
rise still higher, 900 miles above the center OF
the Earth. and there fnd the space through which
this body falls is a ninth part OF sixteen ieet IN
second-here is another confirmation OF the law.
And IT, as increase my distance every time by the
radios OF the Earths circumference, ind the same
law hold true pronounce, without hesitation that
this is the Law Of Attraction.
But | cannot rise in this way TO distance Of
twelve eight or four thousand miles. Yet may
not carry my observations 10 q certain hight Yes
bat to such comparatively small distance that the
difference will be inappreciabe. Alas. for the per
son who undertakes the experiment such Is the
minute difference, even when be has attained the
greatest hight ever attained by man, II cannot be
appreciated
What then was to be done No one could as
cend above the Earth to perform these exPer-
81. mt ali Of IA rh.