These are the original sketches used for the engravings in Day's 1843 publication, "Historical Collections of the State of Pennsylvania" (Philadelphia). They are finely detailed renderings of public and private structures and landscape throughout Pennsylvania. Accompanying these sketches are 150 pages of photocopied letters of Day, from originals at Yale University. These were used by Smith in his book.

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.

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.

Though the Miscellaneous Manuscripts collection is composed of items that do not fall readily into any other existing collection, the two dominant intellectual areas represented in the collection are Early American History and History of Science.