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 two letters in this folder are from April 1917. They pertain to Edison's unsuccessful experiments to develop a method of locating submarines with metal detectors using the principle of the induction balance. Noting that this idea was "the favorite suggestion made by the public," Edison concludes that "this special method is hopeless."