Pickering, William H.

First edition. 4to. 2 volumes: pp. vi, 103 & [109]-162; 3 plates to first vol.; fine in the original printed wrappers, ownership inscription of George Davidson to upper cover of each.

Annals of the Astronomical Observatory of Harvard College vol. LXI parts I-II. These two volumes contain papers by Pickering on a range of subjects, including atmospheric definition and photometry. However, the major papers concern Pickerings observations and calculations relating to satellites of Jupiter and Saturn and to possible planets beyond the orbit of Neptune. Pluto was discovered in 1930, but Pickerings’ investigations, both in the present works and in later publications, suggested a possible large group of bodies. Recent exploration has indeed discovered the presence of two groups of asteroid-type objects beyond Neptune. The signatures on the covers of each volume are likely to be those of the astronomer George Davidson (1845-1911), the surveyor and proposer of the Lick Observatory.