This is a collection of autograph letters, principally to Hosack, but also between other correspondents.

This collection includes ca. 200 letters to and from Harvey's family, concerning Quakers, the Missouri Compromise, slavery, the depression of 1819-1820. There is also a commonplace book (1819-1820, 1821 Aug.), with observations on a balloon ascension of 2 Aug. 1819 from Vauxhall Gardens in England, slavery, Indians, and descriptions of Washington and Baltimore. There are also journals of trips to Niagara Falls and Canada in 1820 and to the American West, from Baltimore to Louisville and back, with an added description of a voyage around Long Island aboard the Robert Fulton in August 1821.

These letters and papers include a memorandum book (1795-1827), lectures on botany and medicine, genealogical materials, committee reports from Columbia College, speeches, minutes of the New York Horticultural Society (1822-1828), letters to Sir James Edward Smith (1817-1826), a receipt book of Alexander Hosack (1781-1801), and diaries of Thomas K. Wharton (1830-1862).

These letters, from the Wellcome Historical Medical Society's collections, are on a variety of topics, primarily natural history and medicine.

Letters and papers to or from American scientists or about America, selected from the Linnean Society's collections. Includes letters to William Swainson from John Abbott, John J. Audubon, Constantine S. Rafinesque, Isaac Lea, and John E. LeConte; letters to Sir James Edward Smith from Jacob Bigelow, DeWitt Clinton, J.F. Correia da Serra, David Hosack, Theodore Lyman, William Dandridge Peck, Rafinesque, and Gotthilf H.E. Muhlenberg; letters to William Darlington; letters to Asa Gray; letters of John Bartram; letters of Peter Collinson to J.F. Gronovius; letters and papers of John Ellis, including letters from Alexander Garden, Samuel Martin, and Bernard Romans; letters to Carl Linnaeus from John Bartram, John Clayton, Cadwallader Colden, Correia da Serra, Peter Kalm, Adam Kuhn, James Logan, John Mitchell, and Charles Wrangel.