What is the nature of these vast concentric circles that surround the
planet with a luminous halo? They are composed of an innumerable number
of particles, of a quantity of cosmic fragments, which are swept off in
a rapid revolution, and gravitate round the planet at variable speed and
distance. The nearer particles must accomplish their revolution in 5
hours, 50 minutes, and the most distant in about 12 hours, 5 minutes, to
prevent them from being merged in the surface of Saturn: their own
centrifugal force sustains them in space.

[Illustration: FIG. 48. Varying perspective of Saturn's Rings, as seen
from the Earth.]

With a good glass the effect of these rings is most striking, and one
can not refrain from emotion on contemplating this marvel, whereby one
of the brothers of our terrestrial country is crowned with a golden
diadem. Its aspects vary with its perspective relative to the Earth, as
may be seen from the subjoined figure (Fig. 48).

We must not quit the Saturnian province without mentioning the eight
satellites that form his splendid suite:

Names. Distance from the planet. Time of revolution.
Kilometers. Miles. Days. Hours. Minutes.
1. Mimas 207,000 128,340 22 37
2. Enceladus 257,600 159,712 1 8 53
3. Tethys 328,800 203,856 1 21 18
4. Dione 421,200 261,144 2 17 41
5. Rhea 588,400 364,808 4 12 25
6. Titan 1,364,000 845,680 15 22 41
7. Hyperion 1,650,000 1,023,000 21 6 39
8. Japhet 3,964,000 2,457,680 79 7 54

Here is a marvelous system, with, what is more, eight different kinds of
months for the inhabitants of Saturn; eight moons with constantly
varying phases juggling above the rings!

Now we shall cross at a bound the 1,400 million kilometers (868,000,000
miles) that separate us from the last station but one of the immense
solar system.

URANUS

On March 13, 1781, William Herschel, a Hanoverian astronomer who had
emigrated to England, having abandoned the study of music to devote
himself to the sublime science of the Heavens, was observing the vast
fields with their constellations of golden stars, when he perceived a
luminous point that appeared to him to exceed that of the o