This folder contains material pertaining to a Patent Office proceeding involving Edison's U.S. Patent 648,935 on apparatus for duplicating phonograph records and a competing application filed by Thomas H. Macdonald on June 2, 1900. After being denied a patent by the examiner of interferences, Macdonald pursued the matter through three levels of appeal. The one selected item is Edison's brief in the hearing before the examiners-in-chief.