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 documents in this folder are from March-November 1917 and December 1919. They pertain to Edison's work on a projectile that would penetrate the water without ricocheting and destroy or damage submerged submarines. Included are several photographs of the invention. The letter by Daniels from August 1, 1917 also contains references to Reports 41 and 43. Another copy of Edison's letter of July 27, 1917, with a postscript added at the bottom, can be found in the Josephus Daniels Papers—Thomas A. Edison Correspondence, Library of Congress. The 1919 item is a letter from William H. Meadowcroft to Capt. Lloyd N. Scott. This project is described on pp. 178-179 of Scott's Naval Consulting Board of the United States.