Richmond dispatch. [volume] (Richmond, Va.) 1884-1903, 1888-10-04

cessive evenings with only an average
difference OF 25m. in the time OF rising.
The moon advances eastward in her
orbit about 129 IN "A hours, but tho IN
tcryal between two successive moon
rises varies from 25m. 10 In. lin. If
she moved along the celestial equator
the interval would be about the same,
because the equator is always inclined
the same 10 our horizon. But she moves
nearly along the ecliptic, which IS In
cliRed 23bo 20 the equator, and on ac-
count Of this inclination approaches the
horizon at very different angles at differ
ent times, varying in this latitude from
90 90 10. The full moon is always in
opposition or opposite the sun, which
ct the autumnai equinox is IN the sign
Libra The moon must therefore be
in the sign Aries, the portion OF
her orbit that makes the smallest
angle with the horizon. Sheis therefore
30 near the horizon that though adj
vanciug 12o in her orbit as ususl abe
seems TO rise at nearly the same time for
three evenings The successive risings
of the moon ct nearly the same hour oc-
cur every month, as the moon makes On
entire circuit in month, bat they are
not noticed except when the moon is full
ut this node in Aries, which can happen
only within fortnight Of September 2}d.
Another question proposed asks for
the reason why the full moon "saiis
high in winter and low in summer We
will suppose the moon to move actually
in the ecliptic or suns path. In re-
atty the plane Of her orbit Is inclined -
10 the ecllptic, and excepting at
her nodes or crossing points she
is above or below the ecliptIc.
The inclination is, however, 30 small
that it may be disregsrded. The
full moon is always opposite the SUD, and
at midnight must occupy exactly the OPP
pogte point in the ecliptic to that occu-
pied by the sun at MONDAY. Therefore
in winter, when the sun is lowest, the
moon will no highest, and IN summer,
when the sun is highest, the moon Will
be lowest. We have also more moonlight
in winter because the nights are LONGER
and the moon is in The best position for
lighting up the northern hemisphere.
A third question inquiries why the
moon always shows the same face TO rs.
The moon rotstes on her axis IN the
same time that she makes a revolution
in her orbit, and therefore always pre-
sents the same disc to the earth. If she
had no motion in rotation she would
present opposite sides 10 the earth IN OPP
positc parts Of her orbit. But when globe
revolving IN aclrcc around centre turns
always the same hemisphere towards the
centre, she must turn once on her AXIS
while making the revolution. This -
the case with the moon. Our satellite
makes a sideral revolution from star to
star I'm about twenty days. Moan
time the Garth has been advancing IN her
orbit. and II takes the moon two and
half days more TO reach the point where
she will come into the same position IN
regard To the sun and earth. Her syno-
die revolution from one new moon to an
other is accomplished III twenty -nme and
one half DAYS. Although nearly the
same hemisphere is turned towards the
earth the moon has slight oscillatory
notion, called ibration, which allows us
10 see portion Of tire opposite hems-
phcre. lu consequence Of llbration we
sco about iour seyenths Of the surface OF
the moon. The path Of the moon IS a
curve Of the most complicated kind,
whose form and position are both IL a
state OF continual change.