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 letters in this folder are from August 1917. They relate to Edison's work on an instrument that would indicate the presence of dangerous levels of hydrogen gas in a submarine.
This project is described on pp. 182-183 of Lloyd N. Scott's Naval Consulting Board of the United States. A photograph of Edison's invention appears opposite p. 182. Courtesy of Charles Hummel.