N-18-07-24.2 (1918, 1922)
The dated entries in this notebook are from July 1918 and August 1922. The entries for the earlier period may have been copied into the book in 1922. Included are notes copied from N-18-07-18.2, along with abstracts of results from the same source, evaluating various chemical compounds to be used as part of a sound detection device or chalk (phone) electromotograph. The 1922 entries relate to additional experiments performed with chalk phones tested in a variety of circuits, under differing conditions, or using different metallic contacts. The notes indicate that William A. Hayes assisted Edison with these experiments in 1918, while Frederick P. Ott assisted in 1922. The front cover is marked \"Chalk Phone\"" and is labeled \""Chalk Phone Fred Ott.\"" The pages are unnumbered. Approximately 30 pages have been used."