This notebook is a continuation of N-17-09-15. It was used by Edison aboard the USS Sachem in October 1917 in connection with his work for the U.S. Navy during World War I. The entries relate to visibility at sea and to camouflage experiments conducted under various light and weather conditions. These include experiments with ships camouflaged by different means, as well as experiments with painted boards of different shades erected on shore and viewed from Long Island Sound. There are also entries pertaining to a kite rudder and to smoke bombs. At the beginning of the book are two pages of data from September 1908 on daylight illumination, which were apparently copied from a published source. Edison's notes indicate that the Sachem cruised among Gardiners, Plum, and other islands, using Greenport, Long Island, as a base of operations. The front cover is marked "No 3." The pages are unnumbered. Approximately 30 pages have been used.