Juniata sentinel and Republican. [volume] (Mifflintown, Juniata County, Pa.) 1873-1955, 1877-10-03
The Moon.-Dead TO All Intents and Pur
poses, but still Undergoing Changes.

Although the moon may be regarded
a. 10 all intents and purposes dead, il
must not be supposed that no changes
whatever take place upon her surface.
On the contrary, some of the peculiari-
ties of the moon, condition must tend
TO cause even more rapid changes OF
certain orders than take place in the
case of our own earth. Thus the great
length of the lunar day, and the moon 5
waterless condition and rare atmOs-
phere, must help TO cause compara-
lively rapid crumbling of tie moons
surface. During the long and intensely
hot lunar day the rock substance of the
moons surface must expand cOnsidera-
bly,, for il is raised to degree of heat
exceeding that of boiling water. Dur
ing the long lunar night the surface is
exposed to a degree of refrigeration far
exceeding that Of the bittereSt winter
in the Arctic regions, and must con-
tract correSpondingly. This alternate
expansion and contraction must gradu-
ally crumble away all the loftiest and
steepest portions of the moons surface,
and will doubtless, in the long run
that is some few hundreds of millions
of years hence-destroy all the most
marked Irregularities of the moons
surface.
The eases or changes which have been
recognized by telescopists who have
carefully studied the moons surface,
may all, without exception, be referred
To this process Of gradual, but steady,
disintegratiOn. The most remarkable
case hitherto known, for example, the
disappearance of the lunar crater Lime
Is far better explained in this way than
as the result of volcanic OutburSt. This
ease has recently been described as fol-
lows by the present writer In the
lunar Sea of Serenity there was once a
deep crater, nearly seven miles across,
very distinct and obvious feature,
even with the small telescops less than
four inches in aperaturel used by Beer
and Madler in forming their celebrated
chart. But, ten years ago, the astron-
omer Schmidt, selenographer of sell
enographers who has, in fact, given
the best energies of his life 10 moon
gazing, found this crater missing.
When he announced the fact to the
scientific world, other astronomers,
armed with very powerful instruments
looked for the crater which had been
so clearly seen with Madler's small tel
eScope; but though they found a crater
it was nothing like the crater described
by Nader. The present crater is
scarcely two miles in diameter. and
only just visible with powerful rele
scopes; all around it there is a shallow
depression, occupying region about
as large as the whole crater had been
before.
1t seems impossible to doubt that
great change has taken place here, and
the question arises whether the change |
has been produced by volcanic activity
or otherwise. Sir John Herschel pro-
nounced somewhat confidently in favor
of the former hypothesis. ''The most
plausible conjecture" said he, ''as to
the cause of this disappearance seems
10 be the filling up Of the crater from
beneath, by an effusion of viscous lava,
which, Overlooking the rim on all sides
may have so flowed down the outer
slope as to efface its ruggedness, and
convert ii into gradual declivity east
ing no stray shadows" but how ire
mendOus the volcanic energy" we note
in the passage referred TO, required to
fill with lava crater nearly seven
miles in diameter, and more than a half
deep, The volcanic hypothesis seems
on this Occount utterly incredible, for
if such energy resided in the moons
interior we should find her whole sur
face continually changing. Far more
probable seems the idea that the wall
Of this crater has simply fallen in scat
Iering its fragments over what had once
been the floor of the crater. The forces
Al work in the moon are quite compe-
tent 10 throw down steep crater walls
ike those which seem formerly To nave
girt about this deep cavity. The Corn
tW Ndgd=iEe. {
The Story of a Goat.