sion between them. We see in the outer ring the
faint traces of the line by which it is divided, and inside the inner
ring we have a view of the curious and semi-transparent crape ring. The
black shadow of the planet is cast upon the ring, thus proving that the
ring, no less than the body of the planet, shines only in virtue of the
sunlight which falls upon it. This shadow presents some anomalous
features, but its curious irregularity may be, to some extent, an
optical illusion.

There can be no doubt that any attempt to depict the rings of Saturn
only represents the salient features of that marvellous system. We are
situated at such a great distance that all objects not of colossal
dimensions are invisible. We have, indeed, only an outline, which makes
us wish to be able to fill in the details. We long, for instance, to see
the actual texture of the rings, and to learn of what materials they are
made; we wish to comprehend the strange and filmy crape ring, so unlike
any other object known to us in the heavens. There is no doubt that much
may even yet be learned under all the disadvantageous conditions of our
position; there is still room for the labour of whole generations of
astronomers provided with splendid instruments. We want accurate
drawings of Saturn under every conceivable aspect in which it may be
presented. We want incessantly repeated measurements, of the most
fastidious accuracy. These measures are to tell us the sizes and the
shapes of the rings; they are to measure with fidelity the position of
the dark lines and the boundaries of the rings. These measures are to be
protracted for generations and for centuries; then and then only can
terrestrial astronomers learn whether this elaborate system has really
the attributes of permanence, or whether it may be undergoing changes.

We have been accustomed to find that the law of universal gravitation
pervades every part of our system, and to look to gravitation for the
explanation of many phenomena otherwise inexplicable. We have good
reasons for knowing that in this marvellous Saturnian system the law of
gravitation is paramount. There are satellites revolving around Saturn
as well as a ring; these satellites move, as other satellites do, in
conformity with the laws of Kepler; and, therefore, any theory as to the
nature of Saturn's ring must be formed subject to the condition that it
shall be attracted by the gigantic planet situated in its interior.

To a ha