This notebook is a continuation of N-18-07-1. It was used by Edison primarily in July-October 1918 in connection with work performed for the U.S. Navy during the World War I. Two additional entries at the end of the book are from February 1920. Many of these notes were probably made at Glenmont, Edison's home in Llewellyn Park, where he was working with James M. Burns, John A. Hanley, William A. Hayes, Sherwood T. (Sam) Moore, and other employees on a series of experiments pertaining to the measurement and detection of sound under water. One entry was made at a lake near Bedminster, New Jersey, with Mina Miller Edison accompanying her husband on the trip. Included are tests with various devices to pick up and amplify simulated submarine noises. Many of the experiments involve microphones constructed with granules of carbon suspended in kerosene or other liquids. Other components employed include brass and rubber tubes, telephone receivers, audions, and many experimental electromotograph (chalk) telephones. One entry describes a series of experiments with water tube resonators. The entries from September and October record a series of experiments with more than seventy different substances tried in electromotographs. The notes from February 1920 form a continuation of these experiments and include a series of experiments with resonators. Inserted into the book are ten loose pages of notes and drawings by Edison pertaining to the same electromotograph experiments. The front cover is marked "No 3." The pages are unnumbered. Approximately 130 pages have been used. Courtesy of Thomas Edison National Historical Park.