New-York tribune. [volume] (New-York [N.Y.]) 1841-1842, 1841-12-29

OF the first magnitude Mill -, =. .bo
completely freed his mnd treui 'tie w - ,Lo,,r,
and uniformity were the conditions
oe ;csl ,erfscton a. applied 10 Hot.n. otlil
~ 80 70 feel that the observations OF the An
-. had not been carried to sufficiently great
sxsnt aud he believed it his duty, prescribed alike
nv reason and philosophy, to open the BOOK OF Ma
,nr. and read it with more careful diligence he
selected The first Subject 81 his Inquiries the or
bit of one of the most interesting, because one Of
the nearest planets to our Earth-that OF Mars.
KEPLER carefully observed the ways and going
of that planet; be watched it from day to day and
tracked it in ts march through the painless a5y-.
Of space. b, series of observations easily made
hEPLEg was able 50 ascertain from week to week,
and from month to month, the distance OF Mars
from the Sun ana ne not little startled at
first finding iha, this distance not always the
same. As happens IN every new discovery, ne at
first supposed tina; this was the result Of an error
in his calculations This at least is proof OF hG-
mility--that he man of science should rather be-
lieve his observations erroneous than that ne has
discovered = new truth. kEPEEE believed AT first
that his observations OF Mars wrong, because
they showed that this planet not always at the
same distance from the Sun. He soon toEnd.
however that the results Of hs inquiry had char
acter which error always waEts-that oil uniformity
and consistency; that they had IN fact, the char
| ac,er OF truth He soon became con.cous Of thi.
undeniablc aud naked fact that Mars was not al
WAYS at the same dis :ance from he Sun but cling
ing. with all the lenaclty oi prejudice TO the Old
system ctcircularty, than give up ms darling
hypothesis, he sill assumed that it did move in
| circle, bat that the Sun was not in is centre
Thus, without sacrificing his theory. he accounted
er the fact that Mars constantly changing his
distance from the Sun
Bun having once broken the ice Having once
fallen upon the iaestimabe practice Of careful in
vesti.ation instead OF bndly following old and
rooted theories, keller pursued his observation.
on the orbit OF Mars. He asceuained In each
successive position the distance of Mar. from the
Sum- and thus enabled, any one weuld De,
to lay down his orbit upon chart. When lie had
done this, and cndeavored TO account according 10
his observations for its distance at each successive
interval, he found that circular orbit would
not do il: for the path laid down represented the
orbit not circular, with the Sun either in out
! of the centre He pursued his inquiries .till far
Their; and after carefully comparing his own OBJ
s.rvations with all those of his predecessors
which he could lay his hands he became convinced
that the path of Mars, instead of being circular was
an oyal-was in fact ellipse. He found also that
the Sun by no means in the centre, but aside
from this near one end Of the a:-tha, in fact it
at of the two points in clipse called
foci.
Thi, was a discovery Of capital description
1t Immediately subverted the received principle
of Astronomy. BRt kEPLtR did not stop here.
Having once discnchanted himself of his prejudice
for circularity, being convinced that it
not attribute OF perfection, he began TO consider
whether uniformity of motion necessary at
tribute and from careful observation nc found
that the rate of motion which Mars had in bis
orbit was not uniform. He soon saw tina, the
farther the planet from the Sun the slower he
moved, and the nearer he was the faster he re-
voved in his orbit. The principle of uniformity
was thus at dashed to pieces as completely
that Of circularity had already been Having
satisfied himself that the motion OF Mars was
not unitorRl his next inquiry after the law,
the rule, the physical principles which governed
motion for, that II was subject TO some law he
had no doubt He observed the fac, that The We
Iocity continually increased As the distance from
the Sun diminished, and thence concluded that
here must be some close connection between the
motion and the distance: and after patient in.
vestigatlen, worthy Of modern times enlightened
by the iRductive philosophy of BACON, kEPLER
arrived al another grand law OF Nature. II, he
found, we imagine string 10 be carried frem
Mars TO the centre OF the Sum- and the planet |
sweeps around this luminary if we mag zine the
string to sweep over The space included between
the two bodies, that string will move over equal
spaces in equal times not that the distance
PASSED over by Mars in his orbit will be equal in
equal times, but The dreaS-the number OF acres
,r square miles if you choose swept over by the
.tring joining Mars and the Sun will be always I
equal for equal time The number of square
miles passed over in one haur will be the same rs
the number passed over in the next succeeding
hour, and so for all the rest. Thus instead OF the
theory Of uniform velscity substituted that OF
laform swept over by this connecting line.
Here then was another law of the highest order
of generality Bat as yet this law had only been
established with reference to single planet
kEPLER had only applied it To Mars. But once
engaged in this investigation, his natural keenness
of mind led him 10 obtain the OF extending
II all the planets an1 he found that they all move
in paths round the sun, not his predecessors had
always supposed, in circles, bat in ellipses with
the Sun in one focus and that they all sweep
around the Sun, not with uniform motion, but with
velocity in virtue OF which the space swept over,
by line Joining them to the Sun, would be equal
Tor equal times. These we're tive of the first grand
results OF the inquiries OF this great astronomer.
Another of scarcely less importance has Joined
with these to confer Immortality upon ms name
In comparing the times required by the different
planets to complete their revolutions aroend the
Sun, and in reference TO the mean or average dis
lance OF each, he discovered still more striking
fact namely, that ii you take the number OF
days required by any two planets to sweep around
the Sum- the squares Of these will always have the
same proportion 10 each other the cubes s.
their mean distances from the Sun This law
expressed by this familiar formula: that The
squares Of the periodic times IN The same
proportion as the cubes 81 the distances.
These three grand principles have conferred inn
mortality on the name of kErLER. He was