This undated notebook was used by Edison, possibly during 1920, for rough notes and calculations pertaining primarily to the electrolytic manufacture of nickel flake for use in the positive electrode tubes of the Edison storage battery. Included are references to the cranes, tanks, and labor employed, as well as notations regarding current ratings, time allowed, and costs incurred or saved. Inserted into the book are circular advertisements and letters [not selected], addressed to Mina Miller Edison and dated 1918. The back flyleaf has been torn from the book, apparently after being annotated by Edison. The pages are unnumbered. Only 20 pages have been used. Courtesy of Thomas Edison National Historical Park.