Mineral Point tribune. (Mineral Point, Wis.) 1869-1938, 1892-04-30

ence Is sufficient TO produce considerable
variation In its apparent size and brillian.
cy. Though Saturn appears to travel so
slowly over the ornament, the planet is
in reality moving through space at the
rate of p, 900 miles per hour.
The diameter OF Saturn is about 20, 500
miles which Is nearly nine times that OF
the earth. Its volume is about $50 times
that of the earth, but the mass of the
planet does not exceed the earth mass in
50 great proportion, being a little less
than One-thlrd that Of Jupiter, but about
three times that of the six smaller planets
taken together. The density of Saturn is
very low, being much less than that of
water, and about the same as that of pine
wood 1t is a little more than half as
dense as Jupiter, and nine times less dense
than the earth, so that nine cubic feet of
Saturn, would on the average, contain
the same amount of matter as one cubic
foot of the earth. Prof. Newc0mb saws
st is remarkable for its small density.
which. 30 far as known, is less than that
OF water, consequently it cannot be com
posed of rocks like those which form our
earth.
When powerful telescopes are directed
upon the planet Saturn dark belts are fire.
quently observed on its surface, similar in
appearance to those of Jupiter, though
far more faint and obscure Vast aud
sometimes remarkably sudden changes in
the number and appearance of these belts
have been observed to take place. which
have led astronomers to believe that Saturn
Is enveloped in an atmosphere Of great
extent and density. About the polar
regions of Saturn Sir John Herschel fire..
quently observed slight changes in its
light, and also the appearance Of extensive
cloudy spaces, Witch has still further in
creased the evidence of the existence of
a dense surrounding atmosphere.
In the year 1898 Sir William Hersehel
approximately determined the length of
Saturn's day, or the time required to ro-
tate once upon its axis This was accom-.
plished by repeatedly observing the faint
spots which sometimes, though very sci
dom, appear upon the belts of the planet.
Herschel watched them with great care
through one hundred rotations of the
planet examining them under varied cir
cdmstances, and aspects, and at length
came to the conclusion that Saturn com
pletes a revolution upon its axis in 10
hours, Is minutes and 4 seconds. The only
favorable opportunity for determining its
time Of rotation, since the observations of
Herschel, was on Dec. 7, 1876, when Pro-
fessor Asaph Hall, of Washington (the
famous dlscoVerer of Mars moons). oh.
served a brilliant white spot near the
equator of the planet, which appeared
suddenly as If there had been an immense
Eruption upon its surface. Such a re.
markable and extraordinary phenomenon
had never before been observed upon this
planet. The singular spot elongated itself
In an easterly direction, and continued
visible for near y month, enabling Pro
lessor Hall to make observations from
which he tcdnd that the period of Saturn's
rotation was 10 hours, x minutes and "A
seconds, or less than one-half of one day.
The orbit in which Saturn reyolves
around the sun is inclined to the earth's
orbit, or ecliptic, at an angle of about two
and half degrees, and the axis Of the
planet Is inclined twenty seven degrees
from perpendicular TO its orbit-a posi-
ton which tends to give 20 this planet
nearly the same diversity Of seasons as
that ~hlch we enjoy or earth, though,
owing to the immense, distance of Saturn
from the SUI, the amount of light and
heat at TINS planet is one hundred times
less than that which we received from the
great central luminary of the solar
system.
Saturn Is accompanied during its Journey
through space by family of eight moons
or satellites, which must greatly add TO
the beauty Of the glorious planet. Saturn
Is provided with twice the gratest number
OF moons known to surround any planet.
The names they have received, in the
order OF their distance from the planet.
are Mlmas Encelaous Tethys, Dione,
hhea, Titan Hyperion, and Je ptius
The two Inner satellites, at the time of
their discovery by Sir William Herschel
IN 1883, were seen to thread, like beads
the thin silver line of light" to which the
ring OF Saturn, then seen edgewise, was
Notwithstanding off it at either end,
speedily returning, aud then concealing
themselves behind the planet. The late
Professor Proctor, 10 ms excellent work,
"Halt Hours with the Telescope" saws Of
Satuu's mO0n'a: 80 far as my own ax.
perleoce goes / consider that the five
larger satellites may be seen distinctly in
go f.Ht''AAAA " lal q AED1 LnEtt ana
one half inch aperture. have never seen
the@ with such an aperture. but | Judge
ir2m the distinCtness With which these
satellites may Toe cen with a four inch
aperture. The writer has frequently
seen the five largest satellites. under favor
able conditions. though a four-inch tele-
scope, and exhibited them b others. with
powers varying from 100 to $50 An the
satellites rev7ive around Saturn in elliDti
cal orbits, and each is believed to rotate
once upon ITS axis in the same time that II
completes arevolu'ion, always presenting
one side TO the planet as our own moon
does IN moving around the earth. These
satellites do not, ike those Of Jupiter.
form a system Of nearly equal bodies.
l Titan. the sixth in order Of distance from
Saturn, is probably larger than any of
jupiter satellites The eighth ALSO
lJapetns), Is q large body. probably al
least equal 70 Juplter's third satellite
But hhea, Dione, and Tethys are much
less conspicuous, and the other three can
not be seen without the aid Of a powerful
telescope "
Japetus, the outermost satellite is ra-
markabs fer the fact that while in one
part OF ITS orbit il is the brightest Of an
the -loors except Titan, in the opposite
80