The papers include correspondence, astronomical notes and calculations, notes and drafts of publications, and lists compiled by Fox of outstanding scientists. The general correspondence covers the years from 1904 to 1941. Of interest are the four letters written in 1909 urging the purchase of the Simon Newcomb Library for the Astronomy Department at Northwestern University. The standard equinox correspondence records Fox's interest in 1915 in establishing such a standard internationally. Also included are miscellaneous astronomical notes and calculations, unrelated to specific publications, followed by notes and drafts of several papers on flocculi (cloudlike shapes of calcium, hydrogen, or other elements, revealed in the solar atmosphere by the spectroheliograph.). Fox's major publication, aside from volumes 1-3 of the Annals of the Dearborn Observatory, is the Rotation of the Sun (1921), found both as a rough draft and as a galley in the papers.