, 1889-12-08
GEOGRAPHY OF THE MOON.
A BRIEF WORD PICTURE OF OUR
NEAREST PLANET NElGH5oR.

Though the moon is so near us when
compared with the other heavenly bodies,
it is still a very long way off when esti-
mated by more ordinary standards.
Under the most favorable circumstances
our neighbor is nearly $50, 900 miles
away, and when viewed from 80 great a
distance objects have to be of consider
able magnitude if they are to be visible
at all. A lunar mountain, even if it
were as great as Mont Blanc itself, would
only be shown like a tiny hillock by our
mightiest telescopes. No object on the
moon could be seen unless it were at
least as large as a town hall or a cathe-
dral. Were the great pyramid of Egypt
on the noon 1t would only seem t. us as
a speck, which an artist who was max
ing a sketch at the telescope would indi-
cate by a dot with his pencil.
SIZES BY COMPARISONS.
There are certain spots or marks on
the moon as seen with the unaided eye
with which every one is familiar. They
can be best observed when the moon is
full, and 1t is a remarkable fact that the
features exhibited by the full moon are
always the same. In fact, the moon al
ways turns the same face to us; we are
never granted a glimpse at the other
side, n as to what that other side may
be like neither 1 nor any n else can
give you the slightest information. The
diameter of the moon is about 1000
miles, from which we infer that the
hemisphere which we do see has an area
about double as-big as the entire surface
OF Europe. Some of those large spots
which form tl,a faott, On tka Coll 1900
are therefore about as large as France or
Spain. These regions have a different
color TO the rest of the moons surface,
and the telescope shows that their floors
are smoother than other tracts of lunar
country.
We are certain that the surface of the
moon no longer contains any visible
water. 1t seems to have penetrated into
the interior of the lunar globe at some
period ages before telescopes were ever
directed to the heavens.
Though the ancient sea basins are the
only conspicuous objects in the naked
eye view of the moon yet when the tel
escope is used these features are not
nearly so interesting as the craters.
These are multitudes of small objects
quite invisible to the unaided eye, though
many of them must be a hundred miles
or more in diameter.
To observe these objects with advan-
tage we should select an opportunity
when the is at or near the quarter.
In any case we should avoid making our
visit to the observatory at the time when
the moon is full. You must remember
that the moon derives its light from the
sun just as tho earth does. The sun il
Eliminates that half of the moon which
happens to be turned toward it, while
the other half is in darkness, and accord.
ingly as we see more or less of the bright
half we see the moon more or less full.
1t is along the diameter of the moon at
the quarter, or at any time along the
boundary between the bright part md
the dark, that the illumination is b, :
suited for rendering faint objects visible.
o NICE o WALKING.
There is m particular kind of object
which specially characterizes the geog-
raphy of the % The type of this OBJ
ject is a ring, and of these rings there
are hundreds. They nave been most care
fully drawn on the charts of the moon,
and, indeed, the great majority have had
special names assigned to them. Let me
try to describe what one of these rings
would actually look like if you were able
to stand on the moon. You would find
the ring to be a rampant of lofty noun
tains, surrounding a rough and rugged
interior. The diameter of this circle will
range from the smallest size that we can
just discern, which will be a few hundred
yards across, up to vast extents of 100
miles or even more in diameter, indeed,
If you were standing in the center of one
of the larger of these rings the range Of
mountains which encircled it would be
invisible to you, because they would lie
below your horizon.
While these are The general features Of
the moons geography, some others may
be noted. There are, for example, lofty
ranges of mountains which, in their alti-
tude and in their massiveness, may be
compared with our Alps or our Apen-
mines, INT which, indeed, have been
also applied with appropriateness to
corresponding lunar objects. Imagine,
however, that a walk On he moon would
be attended with most frightful difficult
ties from the nature of its surface alone,
quite independently of other impedi-
ments of a still more insuperable descrip-
NiOhs u = area VI hiOOh thAAu up
pears to be an utter desert-a desert,
too, not of sand, but of rough rocks,
carven into the widest forms, and pre-
senting every difficulty to one who
should try to owe across such a country.
Lilliputians trying tn run races ovee a
heap of bricks would. l fancy, have an
easy task of it as compared with the
conditions under which you or l would
try to walk upon the moon
You know how in climbing over an
Alpine glacier the presence of a yawn-
ing crevasse is a difficulty which some
times battles the m~ountaineer. The lunar
rambler will find his way occasionally
barred by a fearful chasm half n mile or
more in width, descending to a depth
which his eye cannot fathom. Never in
the course of his travels will he meet
with any features resembling those with
which he is happily familiar oil the
earth. He will never meet with a brook
or river; he will never see a grassy field
or a tree; in fact, water being now en-
tirely absent from the moon, it is almost