This notebook was used by Edison and Walter H. Miller in 1919-1920 for notes on experimental recordings. Some of the experiments took place at the Columbia Street studio in West Orange; others were performed at the Edison company's New York studio. The early entries include substantial comments by Edison. The later entries are all written by Miller, with occasional notations regarding Edison's opinions. Some of the experiments involved the use of a 40-foot horn. Inserted into the book are numerous loose pages of comments by Edison, some of which are summarized by Miller in the book. Most of Edison's notes indicate the page of the notebook to which he is referring. These notes appear on the microfilm immediately following the page to which they are keyed. In addition, there are six loose pages of notes by Miller, which refer to six experiments (#823-#828) at the beginning of the book. These notes appear on the microfilm immediately following the relevant notebook page. The book contains 144 numbered pages, some of which are blank. Several pages were removed from the front of the book prior to pagination.