This letter from Secretary of the Navy Josephus Daniels is from July 1915. It is a request for Edison's help in establishing a "department of invention and development" composed of civilian scientists and inventors to advise the U.S. Navy. The proposed group later became the Naval Consulting Board with Edison as chairman. An online finding aid to the Special Collections in the Navy Department Library is available.
Naval Historical Center, Washington, D.C. -- Navy Department Library, Special Collections