The Dusky Ring is now recognised as a permanent feature of Saturn, but how far it used to be permanent, or how long it has been so, is a matter wrapped in doubt. Recorded observations by Picard in 1673, and by Hadley in 1723, made of course with telescopes infinitely less powerful than those of the present day, seem to suggest that both the observers named saw the Dusky Ring, without, however, being able to form a clear conception that it was a ring. It is strange that during the long period from 1723 to 1838, no one—not even Sir W. Herschel, with his various telescopes—should have obtained or at least have recorded any suspicion of its existence. There is, however, direct evidence that the Dusky Ring is wider and less faint than formerly. This was directly confirmed by Carpenter in 1863, who says he saw it “nearly as bright as the illuminated ring, so much so, that it might easily have been mistaken for a part of it.” In 1883, Davidson found a marked difference in the brilliancy of the two ends (_ansæ_) of the ring. In 1889 Barnard was fortunate enough to observe an eclipse of one of Saturn’s satellites by the ring, but the eclipse, that is the concealment of the satellite, was only effected when it passed behind the bright rings; the dusky ring did not obliterate it, and hence there was obtained a conclusive proof of the transparency of the dusky ring. Barnard further concluded from his observations that there was no separating space or division between the inner bright ring and the dusky ring, as has frequently been represented in drawings. This transparency of the Dusky Ring, as a matter of fact, is therefore undoubted; yet what are we to consider to be the meaning of an observation by Wray in 1861, that whilst looking at the dusky ring edgeways the impression was conveyed to his eye that that ring was very much thicker than the bright rings? A very interesting question which has been much discussed has reference to the stability of the rings. It is generally agreed that the constituent particles of the rings must be in motion round the primary or their equilibrium could not be maintained: almost equally certain is it, and for the like reason, that the rings cannot be solid. Of actual change in the rings as regards their dimensions, we have no satisfactory proof, though authorities differ on the point, some thinking that the rings are expanding inwards, so that ultimately they will come into contact with the ball, whilst others consider no proof whatever of such change can be obtained from any of the observations yet made in the way of measurements.