These are letters and papers relating to North America chiefly from the official correspondence of the Gardens and the correspondence of its two directors, Sir William Jackson Hooker and Sir Joseph Dalton Hooker. There are 2 reels of letters from Asa Gray to the Hookers, in addition to other Gray letters elsewhere in the collection. A few letters (1787) from Americans to William Forsyth, superintendent of the Royal Gardens of St. James' and Kensington.

Collection of 283 letters assembled and presented to the Academy of Natural Sciences of Philadelphia by John Torrey. Correspondents include: Louis Agassiz, Zaccheus Collins, Peter S. Du Ponceau, Elie M. Durand, Asa Gray, William Hembel, Alexander von Humboldt, William H. Keating, James Mease, Samuel G. Morton, George Ord, Charles Pickering, Constantine S. Rafinesque, Benjamin Silliman, Sr., John Torrey, Charles Waterton, Alexander Wilson.

The largest portion of correspondence is with Charles Edwin Bessy on botanical matters, including botanical publications in the United States and Europe, and plants and shell specimens.

These letters discuss the fossils of southern California, as well as Indian artifacts, skulls, languages, ethnography, religion, etc. Most correspondents are represented by only one letter.

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

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.

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.

This is primarily a collection of letters, with some additional documents, concerning Young's interest in botany, geology, mineralogy, and natural history. There is information about Bowdoin College, where he studied under Parker Cleaveland. There is also much on the natural history of Maine, where he was the State Botanist in 1847-1849, and also on the Bangor Natural History Society. There are materials on Brazil in relation to Young's service there as the U.S. consul to Rio Grande do Sul from 1863 to 1873. There are also letters from his brother, John C. Young, and his sister, Sarah Augusta Young.

A miscellaneous collection of letters written by naturalist Louis Jean Rodolph Agassiz concerning a wide range of topics: natural history and naturalists, geology, mineralogy, fossils, publications, expeditions, and the Museum of Comparative Zoology at Harvard, which he founded.

Though the Miscellaneous Manuscripts collection is composed of items that do not fall readily into any other existing collection, the two dominant intellectual areas represented in the collection are Early American History and History of Science.