"The structure and rotation of the galaxy."

In: Proceedings of the American Philosophical Society held at Philadelphia for Promoting Useful Knowledge, Vol. LXIX, 1930. Philadelphia:: The American Philosophical Society, 1930., 1930. 245 x 170 mm. Thick 8vo. Pages 401-417. [Entire volume: xix, 580 pp.]. 4 tables. Dark green buckram, gilt spine. Ex library blind-stamp of the Carnegie Institution of Washington Mount Wilson Observatory. Fine. FIRST EDITION. "But perhaps his most notable achievement was his application of spectroscopic evidence to the problem of galactic rotation and the distance and direction (truncated) of the center of gravity of the galaxy, those being determined from the motions of stars of spectral types O5 to B7 (1930)." DSB, XI, pp. 18-19. (Inventory #: S2584)