AUTOBIOGRAPHY OF SIR GEORGE BIDDELL AIRY, K.C.B., M.A., LL.D., D.C.L., F.R.S., F.R.A.S., HONORARY FELLOW OF TRINITY COLLEGE, CAMBRIDGE, ASTRONOMER ROYAL FROM 1836 TO 1881. EDITED BY WILFRID AIRY, B.A., M.Inst.C.E. 1896 PREFACE. The life of Airy was essentially that of a hard-working, business man, and differed from that of other hard-working people only in the quality and variety of his work. It was not an exciting life, but it was full of interest, and his work brought him into close relations with many scientific men, and with many men high in the State. His real business life commenced after he became Astronomer Royal, and from that time forward, during the 46 years that he remained in office, he was so entirely wrapped up in the duties of his post that the history of the Observatory is the history of his life. For writing his business life there is abundant material, for he preserved all his correspondence, and the chief sources of information are as follows: (1) His Autobiography. (2) His Annual Reports to the Board of Visitors. (3) His printed Papers entitled "Papers by G.B. Airy." (4) His miscellaneous private correspondence. (5) His letters to his wife. (6) His business correspondence. (1) His Autobiography, after the time that he became Astronomer Royal, is, as might be expected, mainly a record of the scientific work carried on at the Greenwich Observatory: but by no means exclusively so. About the time when he took charge of the Observatory there was an immense development of astronomical enterprise: observatories were springing up in all directions, and the Astronomer Royal was expected to advise upon all of the British and Colonial Observatories. It was necessary also for him to keep in touch with the Continental Observatories and their work, and this he did very diligently and successfully, both by correspondence and personal intercourse with the foreign astronomers. There was also much work on important subjects more or less connected with his official duties--such as geodetical survey work, the establishment of time-balls at different places, longitude determinations, observation of eclipses, and the determination of the density of the Earth. Lastly, there was a great deal of time and work given to questions not very immediately connected with his office, but on which the Government asked his assistance in the capacity of general scientific adviser: such were the Correction of the Compass in iron ships, the Railway Gauge Commission, the Commission for the Restoration of the Standards of Length and Weight, the Maine Boundary, Lighthouses, the Westminster Clock, the London University, and many other questions.