n water. He is the lightest, in comparison with his size, of
any of the planets. Therefore he cannot be made largely of solid land,
as our earth is, but must be to a great extent, composed of air and
gaseous vapour, like his mighty neighbour. He approaches at times as
near to Jupiter as Jupiter does to us, and on these occasions he must
present a splendid spectacle to Jupiter. He takes no less than
twenty-nine and a half of our years to complete his stately march around
the sun, and his axis is a little more bent than ours; but, of course,
at his great distance from the sun, this cannot have the same effect on
the seasons that it does with us. Saturn turns fast on his axis, but not
so fast as Jupiter, and in turning his face, or what we call his
surface, presents much the same appearance to us that we might expect,
for it changes very frequently and looks like cloud belts.

The marvellous feature about Saturn is, of course, the rings. There are
three of these, lying one within the other, and separated by a fine line
from each other. The middle one is much the broadest, probably about ten
thousand miles in width, and the inner one, which is the darkest, was
not discovered until some time after the others. As the planet swings in
his orbit the rings naturally appear very different to us at different
times. Sometimes we can only see them edgewise, and then even in the
largest telescope they are only like a streak of light, and this shows
that they cannot be more than fifty or sixty miles in thickness. The one
which is nearest to Saturn's surface does not approach him within ten
thousand miles. Saturn has no less than ten satellites, in addition to
the rings, so that his midnight sky must present a magnificent
spectacle. The rings, which do not shine by their own light but by
reflected sunlight, are solid enough to throw a shadow on the body of
the planet, and themselves receive his shadow. Sometimes for days
together a large part of Saturn must suffer eclipse beneath the
encircling rings, but at other times, at night, when the rings are clear
of the planet's body, so that the light is not cut off from them, they
must appear as radiant arches of glory spanning the sky.

The subject of these rings is so complicated by the variety of their
changes that it is difficult for us even to think about it. It is one of
the most marvellous of all the features of our planetary system. What
are these rings? what are they made of? It has