The Welsh non-conformist minister Richard Price (1723-1791) was a moral philosopher and political and economic theorist whose ideas leant support to the American cause during the Revolution. Of broad and liberal mind, he was an integral member of the intellectual coterie surrounding William Petty, the Earl of Shelburne, and was a founding member of the Unitarian Church. Befitting a latitudinarian thinker, the range of Richard Price's correspondence is extremely broad, touching upon his rationalistic philosophy and dissenting theology, his political views on British politics, America and the American Revolution, the Constitutional settlement, the future of the United States, social reform, demography, prisons, and slavery. The ninety letters in the collection are arranged chronologically, with correspondents including Charles Chauncy (8 letters, 1772-1779), Benjamin Franklin (7 letters, 1775-1789), John Howard (11 letters and a biographical manuscript, 1770-1789), Thomas Jefferson (3 letters, 1785-1789), Benjamin Rush (8 letters, 1786-1790), and Edward Wigglesworth (3 letters, 1775-1786), as well as lesser known figures such as the reformer John Howard.

Personal and professional correspondence of the chemist Robert Hare, including drafts of letters to editors of journals on such varied topics as fish guano, slaughterhouses, paper money, and the meaning of the term "Yankee annexations." The collection originally contained over 300 scrolls, since disbound, which contained drafts of letters, essays, and lectures, composed by Hare on ordinary sheets of paper, then pasted end to end, and rolled up. The essay and lecture topics include: chemistry, storms, slavery, currency, fire-fighting, capital punishment, railroads, the Smithsonian Institution, Michael Faraday, religion and Spiritualism, riots in Philadelphia, epidemics, underwater blasting, and Ralph W. Emerson; there is some verse. The collection also contains an account book of Hare and his wife, 1806-1829 (180 pp.; B/H22#3); a volume by Hare on Cyclones (tornadoes), n.d. (ca. 60 pp.; B/H22#4); and Samuel Powel, Jr.'s "Short notes on a course of antiquities at Rome... under M. Byre Antiquarian," 1764. (60 pp.).

George Ord made important contributions as an ornithologist and writer but is also famous for his contempt of fellow ornithologist John James Audubon. Throughout his life he published numerous scientific articles and assisted in completing Alexander Wilson's life's work, American Ornithology; or, The Natural History of the Birds of the United States. Ord also left his mark as a member of the American Philosophical Society and as the president of the Academy of Natural Science of Philadelphia. The George Ord collection consists primarily of outgoing personal correspondence to Charles Waterton ranging from 1831 to 1866 that highlights Ord's professional as well as personal affairs, most notably his hostility toward Audubon. The collection is supplemented by correspondence of Ord's to and from various individuals regarding personal and business matters.

The Anthony F. C. Wallace Papers include correspondence to and from 20th century anthropologists, ethnologists, historians, linguists, and psychiatrists and provides a wealth of resources for the study of technological and social change, American Indians, culture and personality, revitalization movements, the anthropological study of religion, and the cultural and biological bases of behavior. In addition to Wallace's correspondence, research notes, and drafts, the collection includes Wallace family correspondence and photographs, as well as Wallace's writings from childhood through recent years.