W. H. STEATENSONN has given the results of his och it is deduced that the old period should be decreased by 0·34 sec.—a small error consideringbservations of the four chief satellites of Uranus (Mon. Na. Roy. Ast. Soc., 108, No. 2 ; 1948) and has arrived at some interesting conclusions. Using 30 inch reflector between January 9, 1947, and April 8, 1948, his observations of the position-angles, of Umbriel, Titania and Oberon showed that there were no appreciable errors in their computed longitudes, so that the assumed periods of these three satellites are correct, or if there are discrepancies they must be very small. In the case of Ariel, the discrepancy between theory and observation of the hour-angle indicated that a correction of + 6·1° to the computed longitude was necessary. The epoch of Newcomb‘s orbit is 1872·0, from whi the shortness of the time between the discovery of the satellite and Newcomb‘s computation of its orbit. The period of Ariel, applying Steavenson‘s correction, is now 2·5203796 days. Revised magnitudes of the satellites are given, and the following magnitudes, which are not based on photometric measures but on Steavenson‘s familiarity with the North Polar Sequence and the fields of numerous variable stars, are closer to the truth than those usually given : Oberon, 13·8 ; Titania, 13·7 ; Umbriel, 14·5 ; Ariel, 13·7. The satellites are brighter than has been generally assumed by 0·2, 0·3, 1·5 to 2·5, and 2·7 magnitudes, respectively. In the case of Titania and Oberon, Steavenson found decided changes in magnitude from night to night during his observations, and the variations seem to indicate that the axis of rotation of one or both of the satellites makes a large angle with the normal to the orbit-plane and may even lie in or at least close to that plane.