The Rings of Saturn

Abstract

IN the interesting account of the observations of Messrs. Henry on the rings of Saturn (NATURE, May 29, p. 105) they seem to consider the bright ring they then saw as new. On looking over my note-book I find I observed indications of such a bright ring extending inwards as far as the limb of ball. The exact words are, “I see a brighter line here,” with a sketch according in position with the position of the ring shown by Messrs. Henry. The date of this observation is November 28, 1881, 11h. 35m. to 11h. 55m. I had noticed a great difference in comparing this observation with the fine sketch (given in “Instruments and Publications of the U.S. Naval Observatory, 1845–1876”) by Trouvelot, made with the large telescope at Washington in 1875. In this sketch this edge, that I saw bright and that Messrs. Henry show brighter, is shown as dull and breaking up. It is true that Trouvelot saw and sketched the other side of the rings, but that will scarcely account for what is certainly a great difference. In the text relating to this drawing of Trouvelot's this occurs: “Of this and the succeeding figures it may in general be said that nothing is laid down which was not seen by more than one observer. The exception to this is in the case of the notches represented on the inside of the outer ring of Saturn, which were seen by M. Trouvelot with the 15-inch telescope of Harvard College Observatory, and again in Washington, and of whose existence he has no doubt.”