New-York tribune., 1841-12-27

nent The leather contains in its pores certain
quantity OF air. which repels the ser Just as II
did in the case Just noticed. The leather was usu-
ally immersed in the liquid for several weeks at
the end of which it would become very well satu-
rated |, occurred 10 some ere that, by placing
it IN vessel and exhausting the air above It. the
air in the pores would make it. escape. and lis sat
uration become comparatively ea.y. Inis i tie
method now adopted. and an operation which tor
merry required moaths Is now performed IN few
DAYS.
The preservation of timber from what Is called
The dry rot depends on the same principle he
mode OF preservation is by forcing solution OF
corrosive sublimate into The pores OF the wood and
in order to do this eiiectually, the exPedents
are re-or;ed - in the cases already mentioned.
This process. has lately obtained 70 great extent
in England 1t /. called kyani=ation, from it.
di.coveIer Ryan Just as Galvansm and other
scientific principles received their names from their
discoveries.
We will now, If you please change to other sub.
jects.
The FINED STARS, NEBuLx, &c.
When had the pleasure Of addressing you At
the last evening, | endeavored 10 explain the
method BY which we form estimate OF the dis
tances magnitude and spendor OF the tixed stars
nearest Z, our system We saw the conclusions OF
Astronomy drawn from due examination OF the
circumstances by which these distances are gov
erned. Now the number OF stars of the FIRST mag
atude to be seen in the heavens is extremely small
not more than fifteen or twenty being visible
Outside of this class the stars OF the second mag
nilude exist in greater numbers. there being from
fifty to sixty known; while there are OF the third
magnitude more than two hundred 10 be seen.
should observe that we are not 10 suppose that
there Is no difference between stars of the same
magnitude in point OF size an4 spendor. Those Ct
the first magnitude are BY no means all equal, as
Sirius, for example. i much brighter than the
Others Nor must it be understood that there Is
any definite line OF demarcation bsiween stars ct
different ma gnitutes he form Of speaking i just
As If should speak OF men Of the first ma snltudc
meaning those above six feet high; those OF tbs
second between six feet aud FIVE feet sin &c
This would be a perfectly arbitrary distinction and
30 Is that OF the stars. Now astronomers have
seen the necessity of some classification Of this sort,
and have, therefore, divided the visible stars into
seven orders or magnitude.-thc smallest being oi
the seventh As To tho number OF the stars, 1t
cannot be told with any approach to accuracy
When get ZIP to those of the fifth, sixth aud
seventh magnitudes, their number is beyond com.
pwtaiion. The probable number which may be
distinctly by the naked eye has been estimated
Al 20 900 but this must be taken as but 4 rough
estimate. When, moreover, we come to apply the
Telescope TO the examination VIC discover a farther
series OF of the eighth, ninth, tenth, &c to
/ the sixteenth and seventeenth lnagntudes which
are far too small to be visible to the naked eye. OF
which appear only a whitish codd, but which
the telescope tells Us composed OF an Infinite
number OF stars, it were powdered over tho sur
face OF the armament.
Ii, now, the nearest fixed s,ar-that one which
can be seen under the most favorable clrcumsian-
ces-be separated from our system by so vas, II
chasm as we found Mt the last evening, what must
suppose to be the case with those of the sixth.
seventh, and stl more Ell the sixteenth magnitude
visible only by the most powerful telescopes ever
constructed But computations have been made
which stl farther excite our wsnder and sstOnlsh-
ment. A star Of the seventh magnitude can easily
be compared with one OF the first, in point of SPLEEN
DOR by the Photometer-Iust as tte hight OF u
sperm candle can be compared with that OF a lamp
Sir JsHN HERscHELL has compared the splendor
OF star of the sixteenth magnitude with that OF
one of the first, and has found that the light of the
latter is equal to three hundred and sixtytwo times
that of the former. From this il may be inferred
that the distance OF star Of the sixteenth magni-
tude is such that it would require thousands OF
wears for It's light to reach our system these con-
-ideratons present to minds most compreheH-
,ve views of the economy of the Universe. For II
light requires thousand years 10 come from one
OF these plainly dsingulshable stars, there can he
no dout that takes twenty times as long TO come
| from others and what are To inter from tins
but that there are visible objects in the universe
which 90 900 wears ago existed rs they are nos
seen Light left these stars 20 900 years ago, and
mas inst reached the earth upon which we i've
For 20 600 years past, thea, these stars, for augh
we know, mny not ave existed. The objccts We
see to day are the objects Of to-day; the Sirius
that TO day is not the Sirius OF to-day. The
light by which it LETT that star three years
ago, and from that day to this we have known mo-
thing OF it. Into what singular historical state
does this view throw creation Our system, then,
exists at an enormous distance from the nearest OF
the fixed stars, and look in what direction may,
the same chasn yawns between us and it.
The telescope of Sir WILLIAM HEKsCHELL was
of a power thar has never been possessed b. any
other and many curious results have flown ron.
his survey of the heavens If cast EYES
upon the different portions of the hrmame2t we
find the very unequaIy distributed, IL some
parts being very closely clustered, and in others
scattered great distances from each other. There
is line across the heavens called The va LacteG.
or Milky Way. presenting the appearance OF mass
of whitish light-trayerslng the whole arch OF the
armament, composed Of stars thchly clustered
together a. TO appear blended into one mass OF
white light. Now after the most close and care
ful investigation, Sir William Hcrschell came TO
this conclusion: that Sun il snc OF vast stra-
tum or bed OF Suns, the length of which is very
great compared with its breadth, and is breadth
great when compared with its thickness. Ia as
sist the Imagination in forming a conception Of
this stupendous idea. DR.. Lardner exh ibtrd copy
of a drawing made by Herschell to illustrate his
theory. The appearance OF this stratum is that
OF an oblong bed of stars, in which they crowd