This notebook was used by Charles T. Dally and one unidentified assistant, primarily during June-October 1919. Each experiment involves a different preparation of ingredients for the disc record blanks. Varnish preparations and baking schedules also vary. The blanks were prepared in 1919 and then inspected in 1920, 1921, and 1923. There is also a series of tests on clay. Inserted into the book is a 6-page list by Edison of projects for Dally, some of which correspond to the experiments in the book. The front cover is labeled "Exp on Blanks 5." The pages are unnumbered. Approximately 130 pages have been used.
Only the list by Edison has been selected. Courtesy of Thomas Edison National Historical Park.