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 a duplicate copy of Edison's letter of January 21, 1918, filed in Report 46, in which he mentions his idea of observing enemy submarine periscopes from portholes three or four feet above the water line. Courtesy of Charles Hummel.