Principally covering botany and agriculture, this collection includes many manuscripts on trees, shrubs, and plants of different species, copies of botanical essays by others, essays on fruit trees, etc., by Auguste Denis Fougeroux de Bondaroy (1732-89), notes and drafts for the latter's revision of Duhamel's Traité des Arbres et Arbustres. Also miscellaneous essays, sketches, and memoranda on bones of birds and animals, electricity, fish, steam engines, ventilation, temperature and air pressure, mathmatics, paleontology ("Observations sur les os d'éléphants fossiles"), chemistry, metallurgy, entomology, architecture, taxidermy ("Méthode pour empailler les oiseaux"); lists of plants; notes on England, Canada, Mexico, China; notes of reading in Pliny, John Evelyn, Alexander Russell, William Derham, and others. An unpublished translation of Jethro Tull's Horse-Hoeing Husbandry, with additions and revisions by Duhamel du Monceau. An alphabetical catalogue of Duhamel's gardens, prepared by Fougeroux de Bondaroy. The collection has manuscript material in pre-publication form along with published material with marginalia for improvements of later editions. There are a multitude of sketches, botanical materials and seed packets. The collection includes lists of American trees and seeds shared with European scientists. Benjamin Franklin acts as a go between French and American botanists and John Bartram sends seeds to France from his garden. Also correspondence (ca. 170 pieces) with, among others, Peter Collinson, Duc d'Aven, Duc de Noailles, Louis J. M. Daubenton, Mathurin Jacques Brisson, Jean François Gauthier, Comte de La Galissonière, Chrétien Guillaume de Lamoignon de Malesherbes, Emerich Vattel. The collection has been described in part by Gilbert Chinard, "Recently Acquired Botanical Documents," APS Proc. 101 (1957): 508: and by Joseph Ewan, "Fougeroux de Bondaroy (1732-1789) and his Projected Revision of Duhamel du Monceau's Traité (1755) on Trees and Shrubs. I. An Analytical Guide to Persons, Gardens, and Works mentioned in the Manuscripts," APS Proc. 103 (1959): 807.

The correspondence is principally to Zaccheus Collins (1810-1840), with bills, receipts, and notes on Rafinesque vs. Parker; letters from Collins, L.A. Tarascon, Lewis C. Beck, John Torrey, and Charles W. Short (1817-1835); and miscellaneous correspondence and documents relating to Rafinesque vs. Parker, with an account of the Felician Society of Feliciana County, Illinois (1820). The writings are chiefly on botanical topics, and include notes and essays on Indians, Blacks, grapes and wine-making, banking, and speculation. Rafinesque's growing interest in Indian antiquities, linguistics, and history is apparent in letters after 1820. There is an account of Rafinesque's scientific travels in North America and southern Europe (1800-1832), and a bibliography. The botanical notes include descriptions of specimens collected by Lewis and Clark, Patrick Gass, and Henry Muhlenberg.

This collection includes letters from, and drafts of letters to, scientists, artists, musicians, soldiers, political figures, and court personages throughout Europe, especially Italy and France. Topics covered range from personal and social affairs to agriculture, botany, geology, natural history, coinage, museum management, politics, weights and measures, current affairs. The collection also includes four diaries, housed separately with manuscript volumes.