Reproduces papers, correspondence and business papers relating to Eli Whitney's interests in developing the cotton gin and the manufacture of firearms employing a system of interchangeable parts. The papers include land records relating to the acquisition of property for the mill site, patents on inventions, account books and other financial records, and contracts and drawings concerning firearms production. Also included in the papers are records of Eli Whitney's estate, papers of Eli Whitney's nephews and son who succeeded him in producing firearms, and personal papers of Whitney and other Whitney family members.