_Further Observations required._—In the case of an object so faint and diminutive as Uranus, a powerful telescope is absolutely required to deal with it effectively. A small instrument will readily show the disk, and present the picture that caught the eye of Herschel more than a century ago, but considerable light and power must be at command if the observer would enter upon a study of the planet’s surface-markings. With my 10-inch reflector I have suspected the existence of the belts, but under high powers the image is too feeble to exhibit delicate forms of this character. It is to be hoped that with the large telescopes now available at various observatories, some attention will be given to this planet, more especially with regard to the study of the belts and determination of the rotation-period. Amateurs will have little trouble in picking up Uranus; his position can be learnt from an ephemeris and marked upon a star-map. A little careful sweeping with a low power in the region indicated will soon reveal the object sought for, and a higher power may then be applied to expand the disk and render identification certain. It may be mentioned as an interesting point that some fifty years after the discovery of Uranus by Sir W. Herschel the planet was accidentally rediscovered by his son Sir John Herschel, who mentioned the fact as follows in a letter to Admiral Smyth, written on Aug. 8, 1830:—“I have just completed two 20-foot reflectors, and have got some interesting observations of the satellites of Uranus. The first sweep I made with my new mirror I _rediscovered_ this planet by its _disk_, having blundered upon it by the merest accident for 19 Capricorni.” Had the father failed to detect this planet in 1781, the discovery might therefore have been made by the son half a century later. Some spectroscopic observations of Uranus made in 1889 with Mr. Common’s 5-foot reflector, appear to show that the planet “is to a large extent self-luminous.” But Mr. Huggins on June 3 seems to have obtained a different result (see ‘Monthly Notices,’ xlix. p. 404 _et seq._). _The Satellites._—For many years it was supposed that Uranus possessed six satellites, all of which were discovered by Sir W. Herschel, but later observations proved that four of these had no existence. They were small stars near the planet. But two of Herschel’s satellites were fully corroborated, and two new ones were discovered by Lassell and Struve. The number of known satellites attending Uranus is four, and it is probable that many others exist, though they are too minute to be distinguished in the most powerful instruments hitherto constructed. The following are the periods, distances, &c., of the known satellites:—