Letters written by Julia Rush, wife of Benjamin Rush, mainly to her husband, with one to Samuel Stockton and one to Mary Rush. Eight letters were written during the 1793 yellow fever epidemic. The letters are not included in Lyman Butterfield's edition of Benjamin Rush's letters, vol. 30 of APS Memoirs (1951).

Sarah Franklin Bache (1743-1808), a Revolutionary War patriot and daughter of Benjamin Franklin, led an active public life according to the standards of womanhood in the late eighteenth century. As the daughter of Benjamin Franklin she had an unusual access, for a woman, to the political life in revolutionary Philadelphia. Although her primary role was of caretaker of her family and home, Bache played an active role in the Revolution through her relief work and as her father's political hostess. The Sarah Franklin Bache papers consist of incoming and outgoing correspondence ranging from 1768 to 1807 mostly of a personal nature to and from friends and relatives. The correspondence of her relatives includes her nephew William Temple Franklin, her brother William Franklin and her children.

This collection contains mostly entomological material, with much information on the description and identification of particular insects, entomological collections, and the study of entomology in Europe and the United States. In addition, there are materials on medicine and hospitals during the American Civil War, on the Corps of Topographical Engineers, the United States Army, on natural history in the United States, and on the LeConte's family. Some letters are written to President Rutherford B. Hayes and concern the Commissionership of Agriculture, for which LeConte was considered, but not appointed. Letters of John Eatton LeConte and Joseph LeConte are included.

The collection contains information on Fox family speculation in western lands, two manuscript maps from the 1790's and 1830's depicting the family's holdings in northwestern Pennsylvania, and a photograph album from the 1890's documenting Chestnutwold, the Fox estate adjacent to Andalusia. Chief correspondents are Samuel and George Fox.

Letters (including some transcripts and photostats) from and to Vaughan from many American and British correspondents, including: Also personal correspondence and business papers of Benjamin, Charles, Petty, Samuel Sr., Samuel Jr., William, William Oliver, and Sarah Vaughan (2 boxes); lectures, mostly in shorthand (3 vols.); a large number of notes and memoranda on a wide variety of topics, such as agriculture, architecture, astronomy, diplomacy, diseases, dueling, electricity, hieroglyphs, internal improvements, medicine, meteorology, land, manufactures, politics, punctuation, religion, silk-manufacturing, stock-breeding, taxation, Unitarianism, Benjamin Franklin, John Locke, Napoleon I, Joseph Priestley, Bowdoin College, town of Hallowell, Maine; notes on the peace negotiations, 1782-1783; miscellaneous legal papers; genealogy of the Abbott-Vaughan families. For a personal account of the collection, see Mrs. Mary Vaughan Marvin, "The Benjamin Vaughan Papers," APS Proceedings 95 (1951): 246-249.

The collection includes letters between Hutchinson and his uncle Israel Pemberton, written while Hutchinson was a student of medicine in London. There are also 12 tickets of admission to medical lectures in Philadelphia and London, including one given by William Hunter, and 3 unused cards of admission to Hutchinson's own lectures. Miscellaneous items include Hutchinson's marriage certificate; genealogical data on the Hutchinson, Hare, and Pemberton families; and stock certificates, 1857-1872, of the McKean and Elk Land and Improvement Company. Materials dated post-1793 are to and from Hutchinson family members.

A physician, natural historian, and professor at the University of Pennsylvania, Benjamin Smith Barton (1766-1815) was one of the central figures in Philadelphia's early national scientific establishment. Having received his medical training in European universities, Barton was appointed Professor at the University of Pennsylvania in 1789, lecturing on botany, materia medica, natural history. A prolific author, he established his reputation as one of the nation's preeminent botanists through his botanical text book The Elements of Botany (1803), but his contribtions to zoology, ethnology, and medicine were equally noteworthy. Barton's monograph on the "fascinating faculty" of the rattlesnake and his efforts in historical linguistics (New Views of the Origin of the Tribes and Nations of America, 1798) were widely read, and his Philadelphia Medical and Physical Journal (1804-1809) was one of the nation's first medical journals and an important outlet for natural historical research. The Barton Papers offer a comprehensive view of the professional work of Benjamin Smith Barton from the time of his return to the United States in 1789 until his death. The collection is divided into five series: Correspondence, Subject Files, Bound Volumes, Graphic Materials, and Printing Plates. The collection includes a particularly valuable series of botanical, medical, and natural historical drawings collected by Barton for research, reference, and publication. Among the many artists represented are William Bartram, Frederick Pursh, Pierre Turpin, and Benjamin Henry Latrobe.