This notebook was used by Edison during May-June 1916 for notes on experiments to improve the surface quality of Edison disc records. There are also notes by Archie D. Hoffman. The entries pertain primarily to experiments 1138E to 1188E. Included are tests involving different presses and varnish compounds, variations in the number of coats and methods of applying the varnish, and differing amounts of pressure and baking schedules. Flaws and successful results are both noted. An entry entitled "discarded moulds" provides the number of molds discarded during the week of May 15-20, along with notations about their problems and defects. Additional entries relate to experiments on edging and edging tools, as well as a "special experiment" involving prints of "Gigue" recorded by violinist Albert Spaulding. There are also entries regarding problems with the powder in the record blanks and crooked holes in the blanks, as well as notes on the number of discarded blanks and why they were discarded. Some notes are in the form of instructions to Hoffman. Inserted into the book is one loose note, probably by Hoffman. The front and back covers are labeled "No 15." The pages are unnumbered. Approximately 140 pages have been used. Courtesy of Thomas Edison National Historical Park.