he was residing at the time with one of his sons. A stroke of paralysis three years previously, had terminated his scientific activity. In early childhood, he developed an extraordinary capacity, for the mental solution of difficult arithmetical problems, which attracted general attention, and secured for him the interest of eminent friends, and the opportunity for a thorough education. In 1854, he graduated at Harvard College, and immediately obtained employment at the Observatory of that

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... tution, where he remained for about twelve years, receiving the title of Assistant Observer in 1863. Very early in this period of his life, he made himself well known as an active and capable investigator by numerous publications relating to practical and to theoretical astronomy. Among these may be specially mentioned a discussion of the proper motion of Sirius in declination. The results, combined with those from the right ascensions of the star, previously obtained by Peters, confirmed the hypothesis of the orbital revolution of Sirius, and indicated a position angle for its companion closely accordant with that found about the same time by actual observation. A catalogue of the declinations of 532 stars, prepared by Safford in 1860, marks the beginning of the work connected with geodesy which occupied him at intervals for a considerable part of his life. The death of Professor G. P. Bond, in 1865, placed him in temporary charge of the Observatory,