Sacramento daily record-union. [volume] (Sacramento [Calif.]) 1875-1891, 1883-03-31
THE xorror OF THE MOON.

From the earliest times recorded in his.
tory, the moon has attracted the attention
of men almost as much as the sun has.
Philosophers have written of it, poets name
| il in song. and lovers of all ages cling to il
as though they owned it. Msgicians have
coniured with it, and men have had so great
faith in its power and influence that it has
been sort OF refuge in distress" And
astronomers, who may be supposed to have
the care of it, have been not little per.
comport itself as it should. Both in an.
cient and in modern times it has, by its
eclipses, furnished food for thought and for
superstition, to the savage aud civilized
alike; and if the true state of the case has
been written up in these Notes, faith in
its power has not been materially affected
by the lapse of ages. Herein is TIE way it
has perplexed astronomers. Ancient his
torlans have mentioned eclipses both of the
sun and of the moon. giving pretty clearly
in several cases the time of the eclipse
the year and the hour of the day. Men
have computed backwards, if we may SO
call it, and have found that with the moons
present rate of motion it would not be in
the position given by the historians. And
the question comes, "Why not p The
only way out of the difficulty seemed to be
to say that the moon now travels faster
than it did then. It SO does But it was
no easy task to explain why ; some called
it "a reproach TO astronomy" until La
Place showed the cause. The quickening
of the moons pace is due to the change in
the shape of the earth's orbit, caused by
the disturbing action of the planets. The
more elongated the earth's orbit the more
the sun pulls the moon away from the
earth the more nearly the orbit becomes
to a circle, the less the force with which
the sun disturbs the moon. And for many
thousand years past the earth's orbit has
been approaching the form of circle, and
will continue to do so for many thousand
years to come. And all the while the moon
keeps drawing nearer and nearer to the
earth, and must necessarily move faster or
fall down. For fifty years astronomers
were content with La Places explanation.
But in 1858 Mr.. Adams, of England, pub
lished paper claiming that part of the
discrepancy in the calculated and the OBJ.
served position of the moon was due to
slowing up of the earth's revolution on its
arcs in fine, that the day is growing
longer than it was, and therefore the moon
seemed to be further east than it should be,
and that the cause of this slower motion
was the brake-like action of the tides. A
few years later Mr. Stockwell, of Cleve-
land, showed that Mr.. Adams had omitted
some terms in his calculation, and thereby
vitiated his work, so that the conclusion
was not allowable from that computation,
and the question Was left in its original
state. Previous tables of the moon would
eighty years the longer the time the greater
the error. Unthinking persons at different
times have therefore declared that the law
of gravity is not true, and occasionally
some one disputes the mathematical DEM
onstration of other propositions, with the
same result as when one runs amuck against
the old multiplication table. The moon is
small, is disturbed by the sun, is disturbed
by the mass of matter about the equator
in fine, it is disturbed by everything that
can get hold of it, but not all the disturb
nces-technically called perturbations-
have yet been reduced to figures, and 30
the errors accumulate little by little. The
most thorough investigation of the histori.
cal side of the question known to me,
is that by Professor Newcomb, of the
United States Navy. The work was print
ed in 1878 at the Government offices in
Washington City. Persons acquainted
with questions of this sort know that it is
utterly impossible to compute the actual
retar5ing influence of the tides on the
earth's motion. If ever it is ascertained
it will be by observation-not by COM
putation. This, then, is the present
state of the question The moon now per-
forms its revolution round the earth in less
time than in past ages. A part of this is
due to change in the form of the earth's
orbit, and part to the retarding action of
the tides, but the exact amount attributa-
bic to each has not yet been fixed. 1t is
also probable, from the extreme intricacy
of the question on one side, and the inn
possibility of solution in regard to the
other, that astronomers will have to con-
tent themselves with approximations more
or less accurate, and correct the tables,
when the errors become too large to disre-
GARD -TR w NJ in Commercial Gazette