This notebook covers the period February 1888-April 1889. All entries are by Edison, except for one entry by Arthur E. Kennelly. Included are notes and drawings regarding a long-distance telephone transmitter using phonograph cylinder technology. There are also entries pertaining to battery experiments, disc phonographs, and a fluorescent light caveat; cost calculations relating to the buildings and employees required for an ore milling operation; and notes and drawings concerning electromagnetism. The pages are unnumbered, and the book has been used in both directions. Approximately 120 pages have been used.

Courtesy of Thomas Edison National Historical Park.