The sun. [volume] (New York [N.Y.]) 1833-1916, 1896-04-12
SCENERY OF THE MOON.
EASILY Studied. As NO mo
PHBRE DIMs THE TIEw.

what oucs Were Thsu~As % n. L,,.-
sess Are Ksewu Now 90 ne ar.., Ne.
prsss,oas, Formerly Filled with w,..-
Perhaps, s-s ~ Fr.s.-. Drv-Euu...
Volcanoes F: sad H.pos,.s ,~A1o--t.,.s
BY SIR ROBERT BALL.
Lowndes's Professor Of Astronomy. University
OF Cambridge.
Notwithstanding that the moon /. 24o, 600
miles distant from the earth, IL would in soma
respects he hardly an exarveration TO assert
that wo are better acquainted with the topog.
raphv Of our satellite than we arc with that OF
tho globe which forms our home. No doubt IL
may at once DO admitted that with respect to q
largo portion or the moon. jewellers on the earth
are necessarily In total ignorance. 1t is q pc
culiarity OF our satellite that IL manages It's
movements In euch q manner 40 70 withhold
nearly half OF its surface from ever being In
spcotcd. IL follows that We have no means OF
learning What II on the other side Of the moon.
! do not suppose, however. that in these days
any one believes that II we could see II we
would ind any characteristic difference bc-
tween the scenery on the remote side Of tho
moon and on tho side which Is turned toward
the earth. So far, however, as the neighbor-
Ing globe 10 displayed for our observation, we
can certainly assert that there is hardly q spot
possessing the size of an ordinary parish which
has not been studied and photographed.
sketched by competent draughtsmen. duly laid
down on elaborate charts Of the lunar sur
of a special name.
The circumstances Of the moons situation
render IL much easier for us to survey its seen
cry than IL Is TO survey the scenery of any
other celestial body. For, in the first place,
the moon may be regarded as quite close to the
earth. In comparison with tho distances by
which we are separated from the other heaven
ly objects. Tho sun is nearly four hundred
times as far away as the moon: and that plan
etary globe whose surface we have studied to
the greatest advantaae-I mean. of course,
Mars-is. even under the most favorable con-
ditions. still at q distance from the earth
which Is not less than one hundred and forty
times as great as that Of the moon. But be-
sides It's comparative proximity, there is an
other circumstance which renders It compare
lively easy for US to study the features on our
satellite. II q globe like the earth In size. as
well rs in other particulars. had been situated
At the same distance from us as that at which tho
moon now r~evolves. 1t seems quito possible
that we should never have been able TO obtain
any clear notion as to the geography of such a
globe. For our earth is. of course, surrounded
by q thick coat of atmosphere; this atmosphere
is at all times, and in all parts. more or less
opaque from the presence of large quantities
OF floating material. while there are always
some regions where there is temporarily COM
plete obstruction, from the presence of clouds.
Tho atmosphere would thus oppose great diff
culties to the study of the geography of our
earth by an outside observer. 1t may. indeed. be
we'll doubted whether even the outlines OF the
continents could be completely discerned. not
withstanding that the area of the earth at the
distance of the moon would he thirteen times
larger than that of the moon as presented to us.
For the purpose Of the terrestrial aatron-
omer, 1t fortunately happens that the moon
10 almost entirely destitute of atmosphere. The
features OF its surface are consequently never
obscured by any of those causes which would
tend to hide the features Of the earth from out.
side scrutiny. Whenever the clouds on our
globe are out of the way, It is then possible to
observe tho moon with but little obstruction.
II we alec remember that many of the features
of our satellite arc within reach of a telescope
of comparatively moderate power. It will not
be surprising that the lunar scenery has at.
tracted 30 much attention and that thousands
of minute features on its surface have been
carefully identified. In some cases. accom-
plished observers have devoted themselves
with p~-aiseworthy assiduity to the detailed
examination Of speoial parts on the surface.
It would be impossible to enumerate all the
" = ihhNs Vhooo ~ |
have been directed to the study Of the lunar
scenery. may, however. here mention q few
names, adding the remark that there are
doubtless many others whose valuable labors
could not be overlooked II 1t had been possible
n give a more complete account Of the sub
ject than would he practicable within the linn
its Of the present article.
First. I must mention Mr.. Nasmyth. who |
was at once a famous mechanical engineer. |
. n q ,r z.st,, .-l a I-.,toJ .tIons - 4. |
stars. He employed HE well-earned leisure
in the study Of celestial objects. and he de-
voted e~s pecial attention to the moon. The |
work which he produced in conjunction with
Mr.. Carpenter Is a standard authority on the
lunar scenery, and is perhaps one of the most
beautifully illustrated books that has ever
been devoted to the subject OF the heavens.
I must also refer to Prof. Holden and other
distinguished astronomers at the Lick Observ-
atory. on the top of Mount Hamilton. in Cal
ifornia. They have applied their resources
TO the photography Of the moon with remark
able success. and some Of their pictures of our
satellite have formed the basis upon which
DR.. Weinek has produced exquisite drawings
OF the lunar features.
As, perhaps, the latest book on the topog-
raphy OF the moon. | may mention the elab-
crate work by Thomas Gwyn Elger. who is
himself one of the most assiduous OF lunar OBJ.
He has collected together the most
interesting facts relative to the topography OF
our satellite. I am much indebted to the
various authorities I have named for.informa-
ton which l Am utilizing in the present paper.
When we look up at the full moon, even
without calling the telescope to our aid. we
1t once notice the presence of a number OF large
dark patches. IL Is certainly true that there
are no sheets OF water nor anything like wa
ter at present visible on the moon, even with
IL" highest power OF our telescope. In fact,
there are sound physical reasons WIN 1t does
not seem the least likely that there could be
any water in the fluid form present in our
satellite. At the same time the appearance OF
these dark spots, In days before telescopes were
employed, suggested that those objects were
basins of water. and accordingly they were
a~ncIently called ''seas." In modern days, as
tronomers have somewhat awkwardly re-
tai"ed this name, or Its Latin equivalent, to
tha.o ,.,nIIar darL trarta nnfWtfh- |