This notebook was probably begun in 1887, but the first dated entry is for January 3, 1888. All entries are by Edison. The undated entries consist of notes on substances, taken from the third volume of Watt's Chemical Dictionary. The dated entries include drawings relating to phonograph recording surfaces, the pyromagnetic generator, and electromagnetism. Following these drawings are undated notes and drawings concerning electromagnetic devices (including condensers and a diamagnetometer), dynamo armatures, electric railways, filaments, wax compounds for recording cylinders, and a motograph telephone. Finally, there are notes and drawings from May 1888 relating to the design of an electric typewriter and to battery experiments. The spine is labeled "68." The pages are unnumbered. Approximately 110 pages have been used. Courtesy of Thomas Edison National Historical Park.