Wood County reporter. [volume] (Grand Rapids [i.e. Wisconsin Rapids], Wis.) 1857-1923, 1892-04-28

than onethird 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 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 Newcomb saws:
| ut is remarkable for its small density,
which. so far as known, is less than that
OF water, consequently it cannot be com
posed of rocks like those which form our
cart b.
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 and
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
hight, 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 Herschel
| 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.
/ oi,1l
through one hundred rotations OF the
| planet examining them under varied cir
cumstances, and aspects, and at length
Fcame to the conclusion that Saturn com
pleteS revolution upon It's axis in 10
hours, Is minutes and seconds. The only
favorable opportunity for determining its
| time Of rotation, since the observations of
| Herschel, was on Dec Z, 1876, when Pro-
fessor Asaph Hall, Of Washington (the
famous dIscoverer of Mars moons), oh.
served brilliant white spot near the
equator of the planet, which appeared
suddenly as if there had been an immense
irruption 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 a month, enabling Pro
fessor Hall to make observations, from
which he found that the period of Saturn s
rotation was 10 hours, IA minu ties and "a
| seconds, or less than one-half of one day.
The orbit in which Saturn revolves
around the sun is inclined to the earth s
oruit, or elliptic, at an angle of about two
and half degrees, and the axis of the
planet is inclined twenty seven degrees
| ! -
| tlon which tends to give 20 this planet
nearly the same diversity of seasons as
| that which we enjoy on earth, though,
owing to the immense distance of Saturn
| from the SUI, the amount of light and
heat at this 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 Mimas. Enceladus, Tethys, Dione,
Rhea, Titan Hyperion, and Je plius.
The two inner satellites, at the time of
| their discovery by Sir William Herschel
in 1889, "were seen to thread, like beads,
| the thin silver line of light to which The
ring OF Saturn then seen edgewise, was
misunderstanding off it at either end,
speedily returning, and then concealipg
themselves behind the planet. The late
| Professor Proctor. in his excellent work,
'Half Hours with the Telescope says of
! Saturn's moons: 80 far as my own ex-
perience goes | consider that the five
larger satellites may be seen distinctly in
IN good weather with a good three and
one half inch aperture. have never seen
| theGl with such an aperture, but | judge
| from the distinctness with which these
| satellites may be seen with four. inch
aperture. The writer has frequently
seen the five largest satellites, under favor
| able conditions, though four-inch tele-
scope, and exhibited them to others, with
powers varying from 100 to $50. All the
satellites revoIve around Saturn in ellipti-
cal orbits, and each is believed TO rotate
once upon its axis in the same time that it
completes arevolution, 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.
| Titan. the sixth in order of distance from
Saturn, is probably larger than any of
i Jupiter's satellites. The eighth, also
| (Japetus), is large body, probably at
| least equal to JUPITER third satellite.
| But Rhea, Dione, and Tethys are much
less cons picuous, and the other three can
not be seen without the aid Of powerful
| telescope.
Japetus, the outermost satellite, is re-
markable for the fact that while In one
the moons except Titan, in the opposite
part it is almost as faint as Hyperion, and
can be seen only In large telescopes. When
it is faint. Professor Newcomb says
This popularity has been accounted for
only by supposing that the satellite, like
to the planet, and that one side Of it Is
white and the other intensely black. Tue
only difficulty in the way Of this explana-
tion is that it is doubtful whether any
known substance is so black as ore side OF
the satellite must be to account for such
great changes of brilliancy."
Another singular feature In connection
with this interesting system of satellites
is thus described by Sir John Herschel:
"a remarkable relation subslsts between
the periodic times of the two inner satel-
lites OF Saturn and those of the two next
in order of distance, viz: That the per Cd
of the third (Tetbys) is double that of the
first iMlmasl, and that of the fouri
| (Dione) double that of the second tEnele-
ladus). The coincidence is exact in either
case to about one eighth hundreth part Of
the larger period. Arthur K. Bartlett,