This notebook covers the period July-August 1890. All entries are by Edison. The book contains notes, drawings, and calculations relating to ore milling and electric traction. Also included are draft caveats regarding the belting and separation processes for ore milling, as well as a caveat for an alternating meter. The pages are unnumbered, and the book has been used in both directions. Several pages have been removed from both the beginning and the end of the book. Approximately 140 pages have been used. Courtesy of Thomas Edison National Historical Park.