Although the existence of other satellites of Jupiter was predicted by Sir _Robert Stawell Ball_ (born 1840) soon after the discovery of the fifth, much surprise was created by the announcement, in January 1905, that a sixth satellite had been discovered by Perrine, who, in the following month, announced the discovery of a seventh. These discoveries were made by photography, the objects being very faint. The periods of revolution were found to be 242 days and 200 days for the sixth and seventh satellites respectively, the mean distances being 6,968,000 and 6,136,000 miles. It is possible that they may belong to a zone of asteroidal satellites. In fact, the fifth moon may belong to a similar zone, so that Jupiter may have two asteroidal zones; but this is anticipating future discovery. A particular charm has always attached itself to the study of Saturn, the ringed planet. The magnificent system of rings has for two and a half centuries been the object of wonder and admiration in the Solar System, and accordingly they have been exhaustively studied by many eminent observers. While observing the two bright rings of Saturn on June 10, 1838, Galle noticed what Miss Clerke calls “a veil-like extension of the lucid ring across half the dark space separating it from the planet.” No attention, however, was paid to Galle’s observation. On November 15, 1850, _William Cranch Bond_ (1789-1859), of the Harvard Observatory in Massachusetts, discovered the same phenomenon under its true form—that of a dusky ring interior to the more brilliant one. A fortnight later, before the news of Bond’s observation, Dawes made the same discovery independently at Wateringbury in England. This ring is known as the dusky or “crape” ring.