After employment as a professor of mathematics and a lawyer, O.M. Mitchel found his calling when he was appointed professor of mathematics, philosophy, and astronomy at Cincinnati College (1836). Astronomy became Mitchel's central field of inquiry, and he helped found the Cincinnati Astronomical Society in 1842. Two years later, this society erected an observatory partly funded by donations from the audiences of Mitchel's public lectures on astronomy. Mitchel functioned as director of the observatory, and to gain financial support he published Sidereal Messenger (1846–1848), the first magazine on astronomy directed toward a popular audience. Mitchel worked to create public interest in the astronomical discoveries of his day until his participation in the Civil War brought him a fatal case of yellow fever in 1861.
Walt Whitman may have attended Mitchel's lectures at the Brooklyn Tabernacle in December of 1847. If not present at the lectures, Whitman was certainly familiar with the published transcripts of the lectures, A Course of Six Lectures on Astronomy (1848). Whitman was impressed by Mitchel and published an editorial in the 20 March 1847 Brooklyn Daily Eagle commending Mitchel's work on establishing observatories. Mitchel's lectures are a probable source not only for many of the astronomical details in Whitman's writings, but also for the imagery Whitman uses to describe the solar system.
Bibliography
Beaver, Joseph. Walt Whitman: Poet of Science. Morningside Heights, N.Y.: King's Crown, 1951.
Whitman, Walt. The Gathering of the Forces. Ed. Cleveland Rodgers and John Black. 2 vols. New York: Putnam, 1920.