The Brookhaven leader., 1883-05-31
THE MOONS ROTATION.

OF all the permanent heavenly orbs,
there is none that is so near us, is seen
under so large an angle-or, if you
prefer it, of so large an apparent size
and is at the same time so gently il
Illuminated as to permit men to gaze at
it unintcrruptedly, and is so abundant
" marked with divers figurings of
brighter and darker parts all over its
surface, as the moon.
The well-known changes in general
form of the luminous part of the disc
or sphere, known as the phases of the
moon, arising from the different man
ner in which in which it is illumined by
the sun in the course of the month as
seen by us on the earth, and resulting
in the popular names of New Moon,
First Quarter, Full Moon, Third Quar-
ter and New Moon again-slightly in
terfere with the regular observations of
the minuter markings and details of
the surface above alluded to. But the
phase-etfects are easily allowed for;
and then there comes out this con-
clusion, or statement, in which all OBJ
servers, both past and present, agree
namely, that the moon always turns the
same face of itself towards the earth,
during the whole time of every month
" revolution she makes around it.
Hence also comes the equally undis-
puted fact, that mankind is acquainted
with only one side of the moon, and
never will, in the ordinary course of
nature, know what markings or feat
ures, say of sea or land, plains or
mountains, there may be on the other
side.
How this effect comes about, and by
what physical means it is kept up, not
only throughout the revolution of a
single lunar month, but for tens of thou
sands of such periods, in fact through
out all history-is an interesting branch
in the physical astronomy of modern
times; but not for us to enter into now,
for we have preliminary question Civ
en- to us as our present task-namely,
with regard to the general and indubit-
ably observed fact above alluded to; and
which question may be formulated thus:
What are we to say or to believe as to
1.-the rotation of the moon," after hav-
ing ascertained that it keeps one
face steadily toward the earth, during
the whole of a monthly revolution
around it.
The answer ought not to be difficult;
and, indeed, so early an authority as
Berosus, a Chaldean astronomer in the
fourth century before Christ, is record
ed to have come to the true judgment;
for he announced that the moon rotates
once on its axis in the same time that
it revolves once round the earth; and
that opinion has been held by every
practical astronomer, mathematician
and scientist since the time at least of
Francis Bacon.
But these three titles or professions
by no means include all men, even of
education; for some are occasionally
violent on the other side. 1T is
curious" said one of our latest and
most brilliant of mathematical philoso-
pliers, Clerk Maxwell, "to see how
spectators are led by their neglect OF
the exact sciences, to put themselves
in opposition to them, when they have
not the slightest point of contact with
their systems" And it has always been
so. Whence we find that in the sixth
century A. D., lOgician named Sim
plicius must needs come out to oppose
Berosus and the astronomers by declar-
ing that the observed fact of the moon
always keeping the same face to the
earth during revolution around it,
showed that it (the moon) did not ro-
tate on an axis at all.
Now, if Simplicius had meant that he
was only speaking with regard to what
may be termed "appArent astronomy"
he would have been eXcusable enough,
so far as that mere temporary stepping
stone of apparent, in place OF real and
absolute, astronomy is concerned. But,
unhappily, he did not mean that. He
wished, on the contrary, to expose what
he believed to be an outrageous blunder
of the astronomers at the very begin
ming of their own science, and to have
the honor himself of teaching the world
his own discovery, by truer interpre-
tation of the observed and conceded
facts of observation, that the moon in
space does not rotate, or turn on an
axis at all.
1t is strange, wrote the astronomer
Arago, in the beginning OF the century,
that this class of men can not see, that
if the moon did not turn on its axis, and
did keep one part of its face always
pointed to one particular direction in
space, that we, ON the earth, would
then necessarily behold one side of the
moon in one half of its monthly revo-
luton round the earth, and the other
side Of the moon through the remaining
half. But that class of men, who ex-
is still, are obstinate in not seeing or
understanding the case in this way, and
hence they rush into the open to declare
astronomers mad.
Thus, at the Bath meeting of the
British Association for the Advance
ment of Science there was quite noisy
and abusive irruption of these men,
pronouncing that the idea of the moon
rotating on an axis, when it always pre-
sented the same face to the earth, was
folly. Although, too, they were ad-