This collection consists primarily of letters exchanged between Edison and Secretary of the Navy Josephus Daniels, along with related correspondence. Many of the typewritten letters are accompanied by drafts in Edison's hand. The one item in this folder is from January 21, 1918. It pertains to Edison's idea of using Vickers machine guns (rather than three-inch projectiles) on destroyers and merchant ships to break the protective glass and angle mirrors on enemy periscopes. At the end of the letter Edison announces his intention to borrow a Vickers gun from Secretary of War Newton D. Baker, take it with him to Key West, Florida, and test it on dummy periscopes. Documents relating to subsequent tests on the Vickers gun, including Edison's efforts to develop a more efficient ammunition-feeding mechanism, can be found in Vickers Machine Gun and Ammunition Feeder (1918), Naval Consulting Board and Wartime Research Papers. Courtesy of Charles Hummel.