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 April 30, 1917. It pertains to submarine detection experiments conducted at Sandy Hook, New Jersey, using Bell telephone receivers amplified by an audion. Additional material regarding submarine detection can be found in Reports 9, 27, and 29.