This notebook was used by Edison in June 1917 to record research performed for the U.S. Navy during World War I. This work was probably done in connection with his attempts at aiding submarine detection. Included are cursory specifications for a group of devices, numbered U1 through U21 (and referred to as "galvanometers" in later notebooks such as N-17-06-28), to be used in measuring amplified sound. Also included are notes on a series of experiments with possible amplifiers for detecting sounds. Several notes indicate that Edison was assisted in these experiments by Isidor (Jerry) Chesler and that a "Telephone Audion Expert" was also consulted. One entry involving a failed amplifier contains the notation that "This is Hell -- War is Hell -- The soul of some German must have got into the audion bulbs." The experiments are continued in N-17-06-14.1. Inserted into the book is one loose page of notes, annotated by an unidentified laboratory employee, repeating some of the instrument specifications. The front cover is labeled "U2." The pages are unnumbered. Approximately 65 pages have been used. Courtesy of Thomas Edison National Historical Park.