The Toledo chronicle. [volume] (Toledo, Tama County, Iowa) 1873-1924, 1877-07-12
Cause Of Changes on the Moons Sur.
face.

Altnougn tne moon may be regarded as
to all Intenis and pursoses dead, it must
not be supposed that no changes whatever
take place upon her surface. On the con.
trary, some of the peculia-ities of the
moons 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 moons waterless condition and
rare atmosphere, must help to cause com
paratively rapid crumbling of the moons
surface. During the long and intensely
hot lunar day the rock substance of the
moons surface must expand considera-
bly,, for 1t is raised to degree of heat ex-
ceeding that of boiling water. During
the long lunar night the surface is ex-
posed to degree of refrigeration far ex-
ceeding that Of the bitteIest winter in the
Arctic regions, and must contract CORE
spondiDgly. This alternate expansion
and contraction must gradually crumble
away all the loftiest and steepest portions
OF the moon'ssurface, and will, doubtless,
IN the long run-that is, some few hun.
dreds of millions of years hence-destroy
all the most marked irregularities of the
moons surface.
The cases of change which have been
recognized by telescopists who have care
fully studied the moons surface, may all,
without exception, be referred to the
process Of gradual, but steady, disintegra.
ton. The most remarkable case hitherto
known, for example, the disappearance
OF the lunar crater Lime, is far better ex.
planned in this way than as the result of
volcanic outburst. This case has recently
been described as follows 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 telescope
less than four inches in aperture) used
by Beer and Nader in forming their eel.
ebrated chart. But, ten years ago, the
Astronomer Schmidt, a selenographer of
photographers (who has in fact given the
best energies of his life to moon gazing),
found the crater missing. When he an
nounced the fact to the scientific world
other astronomers, armed with very pow
erful instruments, looked for the crater
which had been so clearly seen with Mad
ler's small telescope; but, though they
found 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 tele-
scopes. All around it there is a shallow
depression, occupying a region about as
large as the whole crater had been before.
II 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 other
wise. Sir John Herschel pronounced
somewhat confidently in favor OF the
former hypothesis. 1.-THE most plausible
conjecture" said he, as to the cause of
this disappearance seems to be the filling
up of the crater from beneath, by an eff
fusion of viscous lava, which, overflow
ing the rim on all sides, may have so
flowed down the outer slope as to efface
its rugsedness and convert it into grad
ual declivity casting no stray shadows"
Z" But how tremendous the volcanic en-
ergy," we note in the passage referred to,
required to fill with lava crater nearly
seven miles in diameter and more than
half mile deepl The volcanic hypothe-
sis seems on this account utterly incred.
ible, for if such energy resided in the
moons interior we should find her whole
surface continually changing. Far more
probable seems the idea that the wall of
this crater has simply fallen in, scattering
its fragments over what had once been
the floor of the crater. The forces at
work in the moon are quite competent to
throw down steep crater walls like those
which seem formerly to have girt about
this deep cavity. "-CornliN Magazine.