David Rittenhouse (1732-1796) was one of the most prominent American men of science of the 18th Century. A skilled instrument maker, Rittenhouse was the an astronomer, playing a major role in recording the 1769 Transit of Venus, among many accomplishments. Rittenhouse also conducted important survey work for the state of Pennsylvania, establishing the state's western border, as well as overseeing the completion of the Mason-Dixon survey. In addition to his scientific endeavors, Rittenhouse's work for American independence places him among the important founding fathers. Subordinating his scientific interests for the greater good of Pennsylvania during the American Revolution, Rittenhouse served as a member of both the Pennsylvania Assembly and the Pennsylvania Constitutional Convention, and held powerful positions on the Pennsylvania Council of Safety and the subsequent Committee on Safety. Rittenhouse also served as the first director of the United States' Mint, at the behest of President George Washington. Rittenhouse was elected to the American Philosophical Society in 1768 and played a major role in placing the Society on the scientific map. He held many positions in the Society, including serving as its President from 1791 until his death in 1796. The Rittenhouse papers span 1774 to 1932, and consist of 61 items, over 0.25 linear feet. The collection is comprised mainly of correspondence, but also includes receipts, genealogies and broadsides.

This correspondence is principally concerned with business between Pershouse and his brother James in England, with comments on conditions and events in the United States, including anti-British feeling, Thomas Paine's return to America, Jefferson's administration, and immigration. The papers include Pershouse's journal (1800-1838), which includes accounts of travels in England, France, and the United States, letterbooks (1836-1862) of Henry Pershouse, nephew of John, chiefly on business matters, and two volumes of Pershouse genealogical data, compiled by B.M. Pershouse Bayley (1899).

The family correspondence of Richard and Sarah Franklin Bache on a variety of topics including references to Benjamin Franklin and his estate. There is also a family genealogy.

An extensive family collection, the Vaux Family Papers center around the lives of George Vaux V (1721-1803), George Vaux VII (1779-1836), and George Vaux VIII (1832-1915), their business partners, siblings, wives, and children, and encompasses the extended Vaux family of Warders, Sansoms, Heads, Graffs, Morrises, Cressons, and Mayberrys. The collection includes correspondence, financial accounts, receipts, business records, journals, diaries, photographs, and legal documents.

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.

The Peale family is best known as a family of artists; however, family interests and activities were much more wide-ranging. The best known Peale is Charles Willson Peale (1741-1827, APS 1786), who produced more than one thousand paintings, including hundreds of portraits of leading Americans during the colonial and early national periods. Peale was married three times, to Rachel Brewster (1744-1790), Elizabeth de Peyster (1765-1804), and Hannah More (1755-1821). He had eighteen children, eleven of whom reached adulthood. Three of Charles Willson Peale's sons became artists: Raphaelle Peale (1774-1825), Rembrandt Peale (1778-1860), and Rubens Peale (1784-1865). A fourth son, Titian Ramsay Peale (1799-1885, APS 1833), was a naturalist (who made drawings on the exploring expeditions he accompanied) and pioneer in photography, and another son, Benjamin Franklin Peale (1795-1870), became a naturalist and paleontologist. Peale's daughter Sophonisba Angusciola was married to Coleman Sellers (1781-1834), an inventor and manufacturer of machinery, including locomotives. Two of their sons, George Escol Sellers (1808-1899) and Coleman Sellers (1827-1907, APS 1872), were inventors and engineers. The latter served as director of the construction of the hydro-electric power development at Niagara Falls. He was married to Cornelia Wells Sellers (1831-1909). One of their grandsons was Charles Coleman Sellers (1903-1980, APS 1979), a librarian and historian and the author of several studies of the Peale family, including a Charles Willson Peale biography.

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.