12 HISTORY OF THE [1820-30 Street, Covent Garden, and was very numerously attended. A paper by the Rev. Dr. Pearson was read on the subject of a new micrometer which he had invented for measuring small distances in the field of a telescope. . . . At this first ordinary meeting, held at eight o'clock on March 10, the Minutes tell us that twenty-eight members were present, Stephen Groombridge being in the Chair. Three new members were proposed, for election (being numbers 84, 85, and 86), a score of book's were presented by Brisbane, Stokes, Hutton, Colby, and Baily, and then Dr. Pearson's paper was read " On the doubly- refracting property of rock-chrystal, considered as a principle of micrometrical measurements when applied to a telescope." The summary of its contents (two pages of MS. minutes) ends with the statement, "The practical application of the micrometer thus constructed the author proposes to communicate at a subsequent meeting of the Society." At the meeting of April 14, Colebrooke was in the Chair ; 22 were present ; 13 new members were proposed ; and Dr. Pearson gave his promised description of the construction and use of his micrometer, producing actual instruments and measures made with them. On May 12, Groombridge in the Chair, 24 members and one visitor present ; 5 new members were proposed ; the 3 proposed in March were elected (thus initiating the adopted practice of election two meetings after proposal). Dr. Brinkley, Professor at Dublin, one of the five proposed, explained that his tardiness in coming forward was due to accidental delay in his receiving the original circular, which he much regretted ; news of the proposal for an observatory at Cambridge was announced ; and Mr. James South read a paper on double stars. On June 9 (Colebrooke in the Chair), no list of members present is given. Eight new members and one Associate (Biot) were proposed ; the 13 proposed in April were all elected, and 2 of the 3 elected in May were formally admitted (there was, however, as yet, no book for them to sign : that came later). Captain Basil Hall announced that he was sailing in a frigate to the south of Cape Horn, and would be happy to receive instructions for nautical observations likely to be of value. F. Baily read a paper " upon a method of fixing a transit instrument exactly in the meridian," and Sir H. Englefield addressed the meeting orally. From the fact that he apologised for doing so, owing to " his present inability to write on any subject " we may infer the rigidity of the rule that communications must be in writing. He drew attention to some old observations which might refer to comets, or perhaps satellites to Venus, and suggested further search.
