The papers of the Italian natural philosopher and electrician, Giambatista Beccaria (1716-1781) contain letters to Benjamin Franklin, Joseph Banks, Laura Bassi, Gian Francesco Cigna, and others on a variety of scientific topics, including atmospheric and terrestrial electricity, the aurora borealis, earthquakes, meteorology, and phosphorescence. In addition to Beccaria's epistolary essays, the collection includes several journals of meteorological observations and notes for Giovanni Eandi's biography of Beccaria.

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.

Through his craniometic studies of human races, the Philadelphia physician Samuel George Morton (1799-1851) exerted a profound influence on the development of physical anthropology in antebellum America, and made substantial contributions to mineralogy, paleontology, and natural history. Relating primarily to Morton's scientific interests, the Morton Papers include insights into Morton's perspectives on education, medical practice, geology and mineralogy, craniology, paleontology, the Wilkes Exploring Expedition (also known as the United States Exploring Expedition 1838-1842), and his two major monographs, the Crania Americana and Crania Aegyptiaca. Several of the letters were written by Morton in his capacity as corresponding secretary of the Academy of Natural Sciences of Philadelphia. Also included in this collection are Morton's "Some Remarks on the Infrequency of Mixed Offspring Between the European and Australian Races" (1850), Joseph Barclay Pentland's notes on the aborigines of Peru (ca. 1840?), and newspaper clippings on Morton's death; a diary of Morton's trip to the West Indies, 1834, a set of craniological sketches for use in Crania Americana, and a microfilm of letters in private hands, written to Morton, 1838-1844