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 two letters in this folder are from April 1917. They pertain to Edison's idea of putting a drum into the recess of a submarine to enable it to maintain its stability without having to keep moving. The letter by Daniels also contains a reference to Edison employee Selden G. Warner, a lieutenant in the 71st New York Infantry Regiment of the National Guard, who was granted leave to assist the inventor in his experiments.