1839 "Cambridge Observatory:--On Mar. 7th I went to Cambridge on the business of the Northumberland Telescope: I was subsequently engaged on the accounts, and on Aug. 16th I finally resigned it to Prof. Challis, who accepted it on Aug. 19th. On Sept. 11th I communicated its completion and the settlement of accounts to the Duke of Northumberland. The total expense was _£1938. 9s. 2d._ + 15000 francs for the object-glass. "At Greenwich Observatory:--On Jan. 3rd I received the last revise of the 1837 Observations, and on Jan. 8th the first sheet for 1838.--In July I report on selection from a long list of chronometers which had been on trial, and on Sept. 2nd I pointed out to Capt. Beaufort that the system of offering only one price would be ruinous to the manufacture of chronometers, and to the character of those supplied to the Admiralty: and that I would undertake any trouble of classifying the chronometers tried. This letter introduced the system still in use (1871), which has been most beneficial to the manufacture. On Sept. 11th I proposed that all trials begin in the first week of January: this also has been in use as an established system to the present time.--It was pointed out to me that a certain chronometer was affected by external magnetic power. I remedied this by placing under it a free compass magnet: a stand was specially prepared for it. I have never found another chronometer sensibly affected by magnetism.--In November and December I tried my new double-image micrometer.--Between May 16th and Oct. 13th a fireproof room was constructed in the southern part of the quadrant room; and in November a small shed was erected over the entrance to the North Terrace.--The position of the free Meridional Magnet (now mounted in the Magnetic Observatory) was observed at every 5 m. through 24 hours on Feb. 22nd and 23rd, May 24th and 25th, Aug. 30th and 31st, and Nov. 29th and 30th. This was done in cooperation with the system of the Magnetic Union established by Gauss in Germany.--The Reduction of the Greenwich Planetary and Lunar Observations, 1750 to 1830, went on steadily. I had six and sometimes seven computers constantly at work, in the Octagon Room.--As in 1838 I had a great amount of correspondence with Mr Baily on the Cavendish Experiment.--I attended as regularly as I could to the business of the University of London. The religious question did not rise very prominently. I took a very active part, and have a great deal of correspondence, on the nature of the intended examinations in Hydrography and Civil Engineering.--On the Standards Commission the chief work was in external enquiries.--On June 6th I had enquiries from John Quincey Adams (U.S.A.) on the expense, &c., of observatories: an observatory was contemplated in America.--I had correspondence about the proposed establishment of observatories at Durham, Glasgow, and Liverpool.