y examined with powerful telescopes during the ten
years following its discovery by Bond, at which time it was most
favourably placed for observation, it was observed that the outline of
the planet could be seen across the entire breadth of the dark ring. All
the observations agreed in this respect. It was, indeed, noticed by
Dawes that outside the planet's disc the dark ring showed varieties of
tint, its inner half being darker than its outer portion. Lassell,
observing the planet under most favourable conditions with his two-feet
mirror at Malta, could not perceive these varieties of tint, which
therefore we may judge to have been either not permanent or very
slightly marked. But, as I have said, all observers agreed that the
outline of the planet could be seen athwart the entire width of the
dark ring. Mr. Trouvelot, however, has found that during the last four
years the planet has not been visible through the whole width of the
dark ring, but only through the inner half of the ring's breadth. It
appears, then, that either the inner portion is getting continually
thinner and thinner--that is, the satellites composing it are becoming
continually more sparsely strewn--or that the outer portion is becoming
more compact, doubtless by receiving stray satellites from the interior
of the inner bright ring.

It is clear that in Saturn's ring-system, if not in the planet itself,
mighty changes are still taking place. It may be that the rings are
being so fashioned under the forces to which they are subjected as to be
on their way to becoming changed into separate satellites, inner members
of that system which at present consists of eight secondary planets.
But, whatever may be the end towards which these changes are tending, we
see processes of evolution taking place which may be regarded as
typifying the more extensive and probably more energetic processes
whereby the solar system itself reached its present condition. I
ventured more than ten years ago, in the preface to my treatise upon the
planet Saturn, to suggest the possibility 'that in the variations
perceptibly proceeding in the Saturnian ring-system a key may one day be
found to the law of development under which the solar system has reached
its present condition.' This suggestion seems to me strikingly confirmed
by the recent discoveries. The planet Saturn and its appendages, always
interesting to astronomers, are found more than ever worthy of close
investigation a