n with the dark
line as seen on the northern side. No doubt could remain as to the fact
that Saturn was girdled by two concentric rings equally thin, the outer
edge of one closely approaching to the inner edge of the other.

At the same time it is right to add that the only absolutely
indisputable proof of the division between the rings has not yet been
yielded by the telescope. The appearances noted by Herschel would be
consistent with the view that the black line was merely a part of the
ring extending through its thickness, and composed of materials very
much less capable of reflecting light than the rest of the ring. It is
still a matter of doubt how far it is ever possible actually to see
through the dark line. There is apparently only one satisfactory method
of accomplishing this. It would only occur in rare circumstances, and it
does not seem that the opportunity has as yet arisen. Suppose that in
the course of its motion through the heavens the path of Saturn happened
to cross directly between the earth and a fixed star. The telescopic
appearance of a star is merely a point of light much smaller than the
globes and rings of Saturn. If the ring passed in front of the star and
the black line on the ring came over the star, we should, if the black
line were really an opening, see the star shining through the narrow
aperture.

Up to the present, we believe, there has been no opportunity of
submitting the question of the duplex character of the ring to this
crucial test. Let us hope that as there are now so many telescopes in
use adequate to deal with the subject, there may, ere long, be
observations made which will decide the question. It can hardly be
expected that a very small star would be suitable. No doubt the
smallness of the star would render the observations more delicate and
precise if the star were visible; but we must remember that it will be
thrown into contrast with the bright rings of Saturn on each margin so
that unless the star were of considerable magnitude it would hardly
answer. It has, however, been recently observed that the globe of the
planet can be, in some degree, discerned through the dark line; this is
practically a demonstration of the fact that the line is at all events
partly transparent.

The outer ring is also divided into two by a line much fainter than that
just described. It requires a good telescope and a fine night, combined
with a favourable position of the planet, to render