Delaware gazette and state journal. (Wilmington, Del.) 1883-1902, 1901-08-08
THE SKIES IN AUGUST.

In the course OF the month OF August
the lunar phases will be follows Last
quarter on the 18th. new on the 18th,
first quarter on the ed, and full on the
18th. The moon will be in rerigee on
the 9Th and in apogee on the Goth.
The moon presents to US some features
no other celestial body dofs, and one Of
these Ia that she always keeps tho same
side toward US. This ia, however, the
natural consequence OF her accomplish
ing one revolution about the earth in
the same time she performs one rota.
| tion on her axis. II is singular that
this appears rather perplexing to not
few, although nothing can be palmer.
| suppose a person moves In circle
while constantly facing an object in
the centre of the circle. When one
circuit Is completed the person has
made one rotation about his axis. Or
else place a ball on the extremity of
crank IN q horizontal position which is
fastened to vertical shaft. Let the
crank reyolve, thus carrying the bal
along. After the crank has made one
revolution the ball has Per formed one
r7tltion. Now some positively deny in
the case OF the person that the person
actually turns on his axis and in the
case of the ball that the ball really
turns on Its axis. They say there lie no
rotation. However, there is nothing
more true than that in either case there
is an actual rotation. The person, as
| we'll as tho ball, has two distinct
motions: first, the motion OF translation,
which carries the centre OF gravity Of
either person or ball 10 a circle around
the centre of the circle or the axis of
the shaft; secondly, an additional
motion of rotation around line drawn
through the centre OF gravity of the
person or hall parallel to perpendicu.
lar through the centre of the circle or
TO the shaft.
The following definition Of rotation is
important and not difficult OF compre
hension: A body "rotates' whenever
line drawn from it's centre of gravity
outward, through any point selected al
random In its mass, describes circle
in the heavens. In consequence Of the
fact that the moon turns on her axis
In the same time in which she make
one revolution round the earth the
earth to al observer on the moon would
never rise or set. At any one place on
the MOON the earth would always be
seen 10 the same place in the sky, sub.
1ect only to slight oscillations from the
lihrations. To an observer in the inidd a
OF the moons disk visible to us the
earth would always be in the zenith;
to one at the edge OF the disk the earth
would always be on the horizon, while
from any point on the other side the
earth, OF course, would never be seen.
Since the phases of the moon depeud
solely uhon the relative position of the
sun. earth and moon, the earth, though
stationary in the heavens to an OBJ
server on the moon, would present all
the phases thenInoon undereoes, but
these rhasss would be exactly opposite
to those Of the moon. When the moon
10 new the earth would be full, ard
while the moon decreases from new to
full the earth would decrease from full
to new. From the fact that to an OBJ
server on the moon the earth would
appear stationary it by no means must
be concluded that the earth would
appear stationary relative to the stars,
for these would rise and set as they do
for us, but it would take them two
weeks, instead of II hours, to pass from
east to west.
The sun during the month of August
will move through an arc OF about 10
degrees north declination, and at the
examination of tho month be nearly o
degrees north Of the equator. Tie
planet Mercury will successfully be in
the consultations of Gemini, Cancer
and Leo, while Venus during the
greater portion OF the month will be In
Leo, put toward the end in Virgo.
Since this planet does not set Before n
little nfter s O'Clock, it may be sean
low down In the west. Mars ia In VIRGO
and later on will be near the first. mag
nitude star Spica, with which ii will
almost simultaneously set at about is
minutes past 10 O'Clock. Jupiter and
Saturn are both adjoining the oonstella.
tion Sagittarius, the former setting
atout ! O'Clock in the morning, the
latter hall an hour later. Sagittarius
Will be on the meridian about 8 O'Clock
10 the evening, and especially favora-
BILE for observation.
We have already on one or two COCA
sionH mentioned that at certain times
the shooting stars appear by many
thousands for few hours, a phepome.
nun called a meteoric shower. While
ordinary shooting stars move in all d.
reoticns, apparently without a system.
at the time OF showers they all seem to |
emanate, or rather radiate from fixed
point, which for this reason is called |
the radiant 1t keeps its place
among the stars unchanged during the |
whole continuance of the shower. just |
according MS the radiant ia situated the |
shower has it's name. The shower
whose radiant IL situated in the con- |
oscillation Leo is called that of the |
Leonids,en thus we have the PerseIds. |
the Lyrids, and others. Now this ar. |
parent radiation of the meteors from
that one point, the radiant, is, how
ever, an effect of perspective. Every
body knows that the rails OF a railroad |
track, though parallel, appear at GER
tam oistance to- meet at q point which |
IS technically called the vanishing
point The meteors actually move in
sensiply straight and parallel lines,
track, seem to meet at that vanishing
point, the radiant Meteor swarms are
just as subject to the attraction of the
sun as the planets, comets or any other
cosmical body, aud 1t follows from this
that the earth can encounter them onlv
when she Is on the point where her
orbit intersects the path Of the swarm.
fhis OF course, must always be on the
same Gay OF the year. except as, in the
course OF time. the orbits Of the meteor
swarms SHIFT their positions in conse.
quence Of perturbations. The Leonids.
whose radiant is in the constellation
Leo, appear about the 10th day of
August, ut which time we may expect
more than the ordinary number of
shooting stars. August and November
are the two months in the year when
these meteoric swarms or showers, that
since the great shower of 1893 have
attracted so-much attention and stimu.
lated astronomers to mako narnfnl in