This account of Thomas Godfrey was prepared "with a view of having it inserted in Rees Cyclopedia," and is preceded by an essay concerning Godfrey and his quadrant taken from the "American Magazine" (1758). Also included in this volume is a copy of James Logan's communication to the Royal Society, and a letter from Spencer to Alexander Wilson, editor of the "Cyclopedia" (1809), which discusses Godfrey and the sources for this account.

A pioneer in ethnographic and linguistic studies of the American Indian and one of the most active members of the American Philosophical Society, Peter Stephen Du Ponceau helped to establish the American Philosophical Society's reputation as one of the world's foremost centers for the study of American Indians and their languages. The Peter Stephen Du Ponceau collection consists of correspondence on legal matters, Indian linguistics, silk culture, maritime law, the American Philosophical Society, and various publications of the early nineteenth century. The collection also includes several essays by Du Ponceau, most of which deal with maritime law.