Though less well known than their peers Lewis and Clark, William Dunbar and George Hunter played an important role in the early scientific exploration of the Louisiana Purchase. While the original goal of organizing a southern counterpart to the Corps of Discovery proved overly ambitious, Dunbar and Hunter provided important geographic information for future explorations and gave the first scientific description of the Hot Springs of Arkansas and Ouachita Mountains. The four surviving journals of George Hunter provide engaging accounts of travel in the Ohio and Mississippi Valley in 1796, 1802, and 1809, and include the most interesting record of the expedition to the Hot Springs of Arkansas in 1804-1805, complete with his detailed notes on natural history and meteorology. The volumes also contain various references to relations with the Delaware, Chickasaw, Choctaw, Cherokee, and Osage Indians. The APS owns a contemporary copy of Hunter's journal ("Journal up the Red and Washita Rivers with William Dunbar"; Mss.917.6.Ex7), from which extracts were printed in Thomas Jefferson, Message... Communicating Discoveries Made in Exploring the Missouri (New York, 1806), and which is described by Isaac J. Cox, "An Early Explorer of the Louisiana Purchase," APS Library Bulletin 1946: 73. The journals were edited by John F. McDermott and published in APS Transactions 53 (1963).

Between 1764 and 1781, the Scots surveyor George Gauld was assigned by the British Admirality to chart the waters of the Gulf Coast off British West Florida, an area that extended from New Orleans to the modern-day Florida. In 1773, Gauld submitted some of his findings to the APS, probably in hopes of having them published in the Transactions, and although these were not published, they became one of the first mansucripts entered into the Society's collections. Contains occasional brief references to Native peoples of the areas described. The Gauld manuscript also includes an extract of a letter from John Lorimer to Gauld, 1772, and a sketch of the Middle and Yellow Rivers of West Florida by Thomas Hutchins. When it was received at the APS, it was endorsed: "This long uninteresting Paper can hardly obtain a Place in the Transactions of a Philosophical Society. It should however be preserved in the Files for the Use of Historians or map makers."

This item is a detailed description of the geography, population, natural resources, and agriculture of the Ouachita River area of the Louisiana Territory. Describes mounds; mentions Cataoulou Indians; also gives figures as to numbers of white and Indian hunters. These pages are a record of travel on a road built between Choctaw and Chickasaw country, with comments on the condition of Indian-white relations, the increase in white population, and Wilson's stay, at Muscle Shoals, with Cherokee chiefs Doublehead and Skiowska. Wilson finds the Indians have good farms, furnishings, fences, and stock, and one Indian runs an inn.