This notebook was used by Edison in September 1918. The entries pertain to the construction of powder blanks for disc records. Included are notes on two standard mixtures for making blanks and three schedules for baking them. The blanks consist of rosin, chalk, and flock in differing proportions, and the schedules involve gradual heating of the blanks before varnishing and printing. There are notes on the viscosity of rosin at various temperatures, the quality of blanks obtained, and the methods of mixing and forming blanks. One entry has a table of "Properties of alloys of Rosin & Resinate of Manganese." Another includes notes on testing various fillers for iron. The notes indicate that William Walter Dinwiddie and Charles T. Dally assisted Edison with the experiments. The front cover is labeled "Edison A" and "The August 1918 Record." The pages are unnumbered. Approximately 25 pages have been used.
Courtesy of Thomas Edison National Historical Park.