This notebook has one dated entry, written by H. De Coursey Hamilton on March 23, 1888, regarding experiments on diaphragms for the phonograph reproducer. At the end of the book are 6 pages of drawings relating to the phonograph. The front cover is labeled "Phonograph." The spine is labeled "59." The pages are unnumbered, and the book has been used in both directions. Only 8 pages have been used. Courtesy of Thomas Edison National Historical Park.