The one dated entry in this pocket notebook is from April 1917. The book was used by Edison, probably during the period April-August 1917, for notes pertaining primarily to war-related experiments. Included are experiments on sound detection devices and other means of locating submarines. There are also references to Edison's work on a "hydrogen detector" that would indicate the presence of dangerous gas in submarines and a "kite rudder" that would enable Allied ships to turn more quickly in case of an emergency. Some of the comments are of a more speculative character such as the idea of using cocaine, morphine, or some other "paralyzing narcotic" in bullets. In addition, there are notes on disc record experiments, an idea for a hornless disc phonograph, and a few remarks about the "Fleming valve" (a vacuum-tube diode invented by John Ambrose Fleming in 1904). Some entries appear to be transcriptions of entries from PN-16-02-15. Among the employees who assisted Edison in his wartime research were Isidor (Jerry) Chesler, Absalom M. Kennedy, William H. Knierim, and Benjamin Liebowitz. Employees mentioned in connection with disc records include William Walter Dinwiddie, Archiebald D. Hoffman, and Josef Miller. The pages are unnumbered. Approximately 150 pages have been used. Courtesy of Thomas Edison National Historical Park.