SATURN. 
pciietratuig smell, and very hot acrid 
ta«te. 
SATURN is a very conspicuous planet, 
though not so brilliant as Jupiter. The 
period of his sidereal revolution round 
die earth is 10,759 days. He moves from 
west to east nearly in the plane of the 
ecliptic, and exhibits irregularities simi- 
lar to those of Jupiter and Mars. He be- 
comes retrograde both before and after his 
opposition, when at the distance of about 
109° from the Sun. His retrograde motion 
continues about 139 days, and during its 
continuance he describes an arc of about 6°. 
His diameter is a maximum at his opposi- 
tion, and bis mean apparent diameter is 18". 
Saturn, when viewed through a good tele- 
scope, makes a more remarkable appear- 
ance than any of the other planets. Gali- 
leo first discovered his uncommon shape, 
which he thought to be like two small 
globes, one on each side of a large one, 
and he published his discovery in a Latin 
sentence, the meaning of which was, that 
he had seen him appear with three bodies, 
though, in order to keep the discovei-y a 
secret, the letters were transposed. Hav- 
ing viewed him for two years, he was sur- 
prised to see him become quite round, 
without these appendages, and then, after 
some time to assume them as before. ^These 
adjoining globes were what are now called 
the ansae of his ring, the true shape of which 
was first discovered by Huygens, about 
forty years after Galileo, first with a tele- 
scope of twelve feet, and then with one of 
twenty-three feet, which magnified objects 
one hundred times. From the discoveries 
made by him and otlier astronomers, it ap- 
pears that this planet is srirrountied by a 
broad thin ring, the edge of which reflects 
little or none of the Sun’s light to us, but 
the planes of the ring reflect the light in 
the same manner that the planet itself does, 
and if we suppose the diameter of Saturn 
to be divided into three equal parts, the 
diameter of tire ring is about seven of these 
parts. The ring is detached from the body 
of Saturn in such a manner, tliat tire dis- 
tance between the innermost part of the 
ring and the body is equal to its breadth. 
Both the outward and inward rim of the 
ling is projected into an ellipsis, more or 
less oblong, according to the different de- 
grees of obliquity with which it is viewed. 
Sometimes our eye is in the plane of the 
ring, and then it becomes invisible, either 
because tire outward edge is not fitted to 
reflect the Sun’s light, or more probably 
because it is too thin to be seen at such a 
distance. As the plane of this ring keeps 
always parallel to itself, that is, its situation 
in one part of the orbit is always parallel to 
that in any other part, it disappears twice 
in every revolution of the planet, that is, 
about once in fifteen years, and lie some- 
times appears quite round for nine months 
together. At other times, the distance be- 
tween the body of the planet and tire ring is 
very perceptible, insomuch that Mr. Whis- 
ton tells ns of Dr. Clarke’s father having 
seen a star through the opening, and stip- 
posed him to have been the only person 
who ever saw a sight so rare, as the open- 
ing, though certainly very large, appears 
very small to us. 
AVhen Saturn appeal's round, if our eye 
be in the plane of the ring, it will appear 
as a dark line across the middle of the pla- 
net's disc, and if our eye he elevated above 
the plane of the ring, a shadowy belt will 
be visible, caused by the shadow of the 
ring as well as by the interposition of part 
of it between the eye and the planet. The 
siradow of the ring is broadest when the 
Sun is nvost elevated, but its obscure parts 
appear broadest when oiir eye is mo.st 
elevated above the plane of it. When 
it appears double, the ring next the body 
of the planet appears brightest. When 
the ring appears of an elliptical form, the 
parts about the ends of the largest axis are 
called the ansce, as has been already men- 
tioned. These, a little before and after 
the disappearing of the ring, are of unequal 
magnitude j the largest ansa is longer visi- 
ble before the planet’s round phase, and 
appears again sooner than the other. On 
the first of October, 1714, the largest ansa 
was on the east side, and on the twelfth on 
the west side of the disc of the planet, which 
makes it pr obable that the ring has a rota- 
tion round an axis. Herschel has demon- 
strated, that it revolves in its own plane in 
10>' 32 ' 15.4''. The observations of tJus 
philosopher have added greatly to our know- 
ledge of Saturn’s ring. According to him 
there is one single, dark, considerably broad 
line, belt, or zone, which he has con- 
stantly found on the north side of the ring. 
As this dark belt is subject to no change 
whatever, it is probably owing to some per- 
manent construction of the surface of the 
ring this construction cannot be owing to 
the shadow of a chain of mountains, since 
it is visible all round on the ring ; for there 
could be no shade at the ends of the ring ; 
a similar argument will apply against the 
opinion of very extended caverns. It is 
pretty evident tliat this dark zone is con- 
