This notebook was used during June-September 1920 by Edison, Walter N. Archer, Frank Detlef, Jr., Howard F. Redford, and possibly other experimenters. The entries pertain to the plating processes involved in the manufacture of disc records. The entries by Edison on the first page consist of a daily record of molds plated in "Bath 7" during June-August. The records, which are continued by Archer, report the date and time, specific gravity, volts, amps, crock temperature, and other conditions during plating. Occasional notes, suggestions, and instructions by Edison are interspersed throughout the early entries. The second part of the book relates to series of experiments conducted by Archer in August in which rubber varnish was used for protection against copper depositing on the backs of the molds. There is also a series of experiments in August and September on transferring molds from the nickel bath to the copper bath without drying after rinsing them free of the nickel solution. One page of instructions from Edison has been inserted into the book. The front cover is labeled "7" and is marked "Disc." The pages are unnumbered. Approximately 100 pages have been used. Courtesy of Thomas Edison National Historical Park.