This notebook was used by Edison in April 1917 to record work for the U.S. Navy during World War I. Included are notes pertaining to a series of experiments with various resonators constructed with tuning forks, phonograph diaphragms, and columns of water of varying heights. One entry gives a description and drawing of a related sound measurement device. Several entries indicate that Edison was assisted in these experiments by Isidor (Jerry) Chesler, who was able to hear sounds that Edison could not. A second set of entries relates to experiments on direction finding for sounds and objects, which were conducted at Sandy Hook, New Jersey, using telephone receivers and funnels. The pages are unnumbered. Only 22 pages have been used. Courtesy of Thomas Edison National Historical Park.