This notebook contains a few dated entries for the period January-April 1888. It was used as an exhibit in American Graphophone Co. v. National Phonograph Co., United States Circuit Court, District of New Jersey. The book consists of notes by Jonas Walter Aylsworth regarding the composition of phonograph cylinders. Included are tests of metallic soap compounds, nos. 20-137, with scattered notations about costs of materials. There are also notes regarding a search for a replacement for hard rubber, and a note by Edison on lamp filament experiments to be tried. Transcriptions of most of these records can be found in N-87-01-01 and N-88-08-23. Only the last page, which was not transcribed, has been selected. Courtesy of Thomas Edison National Historical Park.