This undated notebook was probably used by Edison in 1907 or 1908, but it may have been used as late as 1910. The book contains notes and drawings regarding experiments with the electromotograph, which Edison was using in conjunction with attempts to amplify the sound of a phonograph and for more general work relating to electrical theory. The pages are unnumbered. Only 4 pages have been used.
Courtesy of Thomas Edison National Historical Park.