Vandalia Whig and Illinois intelligencer. [volume] (Vandalia, Ill.) 1832-183?, 1833-10-09
PHYSICAL CONSTITUTION OF
E THE MOON.

VI The physical constitution of the moor
: is better known 10 US than that of an,
: other heavenly body. By the aid Of tel
: escapes we discern inequalities in Its sur
r face which can be no other than noun
5 tains and >alleys-for this plain reason
; that we see The shadows cast by the for
, mer in the exact proportion as to the
5 length which they ought to have whel
we take into account the inclination o
f the suns rays to that part of the moon.
surface on which they stand. The con
veX outline Of the limb turned toward:
the sun is always circular, and very near
~ smooth; but the opposite border of the
enlightened part, which, were the moor
a perfect sphere, ought to be an exac
L. and sharply defined ellipse, is always OBJ
served to be extremely ragged, and in
denied with deep recesses and promincn
points. The mountains near this edge
cast long black shadows, as they should
evidently do, when we consider that the
sun is in the act of rising or setting 10 the
,PaTts OF the moon so circumstanced. But
~ the enlightened edge advances beyond
|ttram, J. c. as the sun to them gains alti-
tude, their shadows shorten; and,at the
iuli moon, when all the light falls on our
line OF sight, no shadows are seen OH any
part OF her surface. From micrometrical
measures of the shadows of many of the
more conspicuous, taken under the most
favorable circumstances, the height of
many OF them has been calculated the
highest one being about one and three
quarters English miles in perpend ocular
latitude. The existence of such noun
talns is corroborated by their appearance
as small points on islands of light beyond
the extreme edge of the enlightened part,
which are the tops catching the sunDeams
before the intermediate plain, and which,
as the light advances, at length onnect
themselves with it, and appear aspromi-
hHnces from the general edge.
The generality of the lunar mountains
present striking uniformity and silgulari-
~ OF aspect. They are wonderfully nu-
merous, occupying by far the larger por
tioh OF the surface, and almost universally
OF an exactly circular and cup shaped
form, foreshortened, however, into eHpses
towards the limb; but the larger have for
the most part fiat bottoms within, from
winch rises centrally small, steep, conf.
car NH. they offer, in short, inits high
est perfection, the true oolcanic character,
as 1t may be seen in the centre Of Vesu.
vius, and in the map of the volcanic dis
iIicts OF Campi Phlegrei, or the Puy de
Dome. And in some of the principal
ones, decisive marks of volcanic stratifi-
cation, arising. from successive dcposites
Oh cJected matter, may be clearly traced
with powerful telescopes.
what Is, moreover, extremely singular
IN the geology Of the moon, is, that al
though nothing having the character Of
'he seas can be traced (for the dusky
spots which are commonly called seas,
"ncn cioseiy examined, present appear
ances incompatible with the superstition
OF deep watcr)yet there are large regions
perfectly level, and apparently Of Il deci-
ded alluvial character.
The moon has no clouds, nor any other
Of an atmosphere. Were there
any, II could not fail to be perceived in
inc occultatlon OF stars and the phenome.
ma ol solar ecIipses. Hence its climate
must De very extraordinary; the aiterna
tlon being that of an unmitigatcd and
burning sunshine, fiercer than an equato-
rial noon, continued for whole fortnight,
and the keenest severity of frost, far ex-
ceeding that of our polar winter, for an
equal time. Such a disposition of things
must produce a constant transfer of what
ever moisture may exist on its surface,
from the point beneath the sun TO that op-
Poslte, by distillation an rae no cryophorm.
The consequence must be absolute arid.
Ity below the vertical sun, constant accre-
ton OF boar frost in the opposite region,
and perhaps a narrow zone of running
water at the borders of the enlightened
hemisphere. 1t is possible, then, that
evaporation on the one hand, and conden-
sation on the other, may, to certain ex.
tent, preserve an equilibrium of tempera.
ture. and mitigate the extreme severity of
both climates.
A circle Of one second in diameter, as
seen from the earth on the surface of the
moon, contains about a square mile. Tel.
Escapes, therefore, must be greatly i'm.
proved, before we could expect to see
signs OF inhabitants, as manifested by edi.
hoes or by changes on the surface Of the
soil. 1t should, however, be observed,
that owing to the small density ofthe ma
te'ials of the moon, and the comparatively
feeble gravitation Of bodies on her sur
lace, muscular force would there go six
times as far in overcoming tho weight OF
the materials as on the earth. Owing to
the want of air, it seems impossible that
any forms of life analogous to those on the