"The Admiralty, on final consideration of the estimates, decided not to proceed with the erection of a new Library near the Magnetic Observatory in the present year. In the mean time the space has been cleared for the erection of a building 50 by 20 feet.--I have removed the Electrometer Mast (a source of some expense and some danger), the perfect success of Sir William Thomson's Electrometer rendering all further apparatus for the same purpose unnecessary.--Many years ago a double-image micrometer, in which the images were formed by the double refraction of a sphere of quartz, was prepared by Mr Dollond for Capt. Smyth, R.N. Adopting the same principle on a larger scale, I have had constructed by Mr Hilger a micrometer with double refraction of a sphere of Iceland spar. Marks have been prepared for examination of the scale, but I have not yet had opportunity of trying it.--The spectroscopic determination of Star-motions has been steadily pursued. The stars are taken from a working list of 150 stars, which may eventually be extended to include all stars down to the fourth magnitude, and it is expected that in the course of time the motions of about 300 stars may be spectroscopically determined.--A new pressure-plate with springs has been applied by Mr Browning to Osler's Anemometer, and it is proposed to make such modification as will give a scale extending to 50 lbs. pressure on the square foot. Other parts of the instrument have also been renewed.--As regards the reduction of the magnetical results since 1863: In the study of the forms of the individual curves; their relations to the hour, the month, the year; their connection with solar or meteorological facts; the conjectural physico-mechanical causes by which they are produced; there is much to occupy the mind. I regret that, though in contemplation of these curves I have remarked some singular (but imperfect) laws, I have not been able to pursue them.--The mean temperature of the year 1879 was 46.1°, being 3.3° below the average of the preceding 38 years. The highest temperature was 80.6° on July 30, and the lowest 13.7° on Dec. 7. The mean temperature was below the average in every month of the year; the months of greatest deviation being January and December, respectively 6.8° and 7.6° below the average; the months of April, May, July, and November were each between 4° and 5° below the average. The number of hours of bright sunshine, recorded with Campbell's Sunshine Instrument, during 1879, was only 983.--In the summer of 1879 Commander Green, U.S.N., came over to this country for the purpose of determining telegraphically the longitude of Lisbon, as part of a chain of longitudes extending from South America to Greenwich. A successful interchange of signals was made with Commander Green between Greenwich and Porthcurno on four nights, 1879, June 25 to 29. The results communicated by Commander Green shew that the longitude of Lisbon Observatory, as adopted in the Nautical Almanac,