This includes communications or correspondence from such figures as A.D. Bache, Amos Bonsall, John F. Frazer, and M. F. Maury. There are reports by committees, such as those on agriculture, botany, horticulture, and meteorology.

This item contains much information about his various posts and about conflicts, personalities, and the politics of science. There are also many references and comments about scientific technology of the day, and of such people as Matthew F. Maury. There are numerous letters to A. D. Bache, James Henry Coffin, Charles Henry Davis, and William H. Willcox.

Mentioned in these letters are personal affairs, experiments, Babbage's calculating machine, and his "Bridgewater Treatise," second edition.

The manuscripts of father William Mitchell and daughter Maria Mitchell are not easily separated, and are treated here together. The collection includes William Mitchell's autobiography, his memoir of Judge Walter Folger of Nantucket, astronomical and meteorological observations, lectures, family and other correspondence.