This notebook contains dated entries from March-April and December 1902 and from October 1903. All entries are by Edison. Included are notes and drawings regarding phonograph recording and reproducing apparatus and the composition of phonograph cylinders. Several entries indicate that some material was transcribed from notebooks used at Edison's laboratory at Fort Myers, Florida. Also included are notes and drawings relating to storage batteries and to an alternating current rectifier. The front cover is labeled "Important Disc Expmts." This may indicate that the book was copied, or referred to, at a later date, since the phonograph entries pertain only to cylinder technology. The pages are unnumbered. Approximately 80 pages have been used.