1860-70] ROYAL ASTRONOMICAL SOCIETY 157 photographic methods, Carrington with practical insight calculated on the probable slowness with which this method would be brought actually into application. Thus it came about that he secured his fine series of visual observations between 1853 November 9 and 1861 March 31, and that the series of drawings made by him on a uniform scale, such that the disc of the sun was a foot in diameter, were available for the measurement of sun-spot areas before the Kew photographs were systematically ready in 1862 February. Carrington's rotation period and his determination of the sun's axis were utilised in all the later reductions. We can well understand that the fact that Carrington and ,De la Rue were Fellow-Secretaries of the Society during the five years 1857-62 contributed in no slight degree to the successful outcome of their labours. De la Rue gave two addresses during his Presi- dency, on the presenting the Gold Medal of the Society, first in 1865 to George Phillips Bond, for his work on the Comet of Donati, and then in 1866 to John Couch Adams, for his contributions to the development of Lunar Theory. G. P. Bond [1825-65] succeeded to the Directorship of the Harvard College Observatory after the death of his father, William Cranch Bond, in 1859 January. He had been an assistant at the Observatory for many years during his father's directorship. The Observatory had been founded in 1839. G. P. Bond had made independent discovery of no less than eleven comets. It is curious that he never mentions in his Memoir on Donati's Comet, which forms volume 3 of the Harvard Observations, and was published in 1862, that the discovery of the comet was made by Donati, nor does he explicitly state the date of discovery, 1858 June 2. The whole period of visibility of that wonderful comet extended from 1858 June 2 to 1859 March 4, an interval of 275 days : it was visible to the naked eye for 112 days, and the tail was visible for 177 days. Bond's Memoir deals with the tails, nucleus, and envelopes of the comet, and is illustrated by more than fifty plates, which exhibit in an admirable manner the changes that occurred from time to time in the wonderful phenomena presented by the comet. The Council's Annual Report in 1859 gave a note of nine pages about the comet. It is not easy to trace the authorship of the early Council Notes. Carrington and De la Rue were Secretaries at the time, and it is not improbable that this note was prepared by one or both of them. It is of very unusual length for the notes contributed in those days, and gave a valuable summary of the phenomena. De la Rue's address gives us some idea of the attention he had himself given to the comet, and it seems not unnatural to attribute the note to him.
