3 papers: (1) "The Brightness of the Stars- Their Distribution, Colors, and Motions." (2) "The General Magnetic Field of the Sun." (3) "The Masses and Densities of the Stars. Contributions from the Mount Wilson Observatory, No. 226."

Offprint from:: Publications of the Astronomical Society of the Pacific, No. 174, April 1918., 1918. 8vo. (228 x 151 mm). 35 pp. Figs., tables. Original wrappers. Very good. (2) Offprint from: The Observatory, Vol. xliii, No. 556, September 1920, pp. (310)-322. 8vo. (213 x 140 mm). 13 pp. Figs. Original wrappers. Very good. (3) [with:] RUSSELL, Henry Norris (1877-1957). "On the Calculation of Masses from Spectroscopic Parallaxes. Contributions from the Mount Wilson Observatory, No. 227." Offprint from: Astrophysical Journal, Vol. LV, 1922. 8vo. (252 x 170 (truncated) mm). 73; 4 pp. Figs., tables. Original wrappers. Very good. Three papers from important American astronomer Frederick Hanley Seares, with an additional paper by Henry Norris Russell. "An early research interest for Seares, which would stay with him throughout his career, was astronomical photometry. With Seares's international experience he began an involvement with the Dutch astronomer Jacobus Kapteyn, and his statistical efforts to determine the shape and size of the galaxy (then widely thought to constitute the whole Universe) by using detailed studies of 252 "Selected Areas" of the sky. Sears's interest was in establishing photographic-photometric standards that would provide accurate magnitude estimates for the stars in the Selected Areas. He would play a major role in establishing the magnitudes of the stars in Selected Areas 1-139. In participating in this effort, Seares would work with a number of the world's leading astronomers and lead the primary effort for constantly refined accuracy in this work." [see Hockey, Biographical Encyclopedia of Astronomers, Vol. 2, p. 1038]. (Inventory #: S9269)