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 been positively proved that they cannot be made of continuous matter, either liquid or solid, for the force of gravity acting on them from the planet would tear them to pieces. What, then, can they be? It is now pretty generally believed that they are composed of multitudes of tiny bodies, each separate, and circling separately round the great planet, as the asteroids circle round the sun. As each one is detached from its neighbour and obeys its own impulses, there is none of the strain and wrench there would be were they all connected. According to the laws which govern planetary bodies, those which are nearest to the planet will travel more quickly than those which are further away. Of course, as we look at them from so great a distance, and as they are moving, they appear to us to be continuous. It is conjectured that the comparative darkness of the inside ring is caused by the fact that there are fewer of the bodies there to reflect the sunlight. Then, in addition to the rings, enough themselves to distinguish him from all other planets, there are the ten moons of richly-endowed Saturn to be considered. It is difficult to gather much about these moons, on account of our great distance from them. The largest is probably twice the diameter of our own moon. One of them seems to be much brighter--that is to say, of higher reflecting