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 documents in this folder are from April 1917. They pertain to Edison's work on an attachment for range finders that would keep the glass of the finder free of spray. A photograph of the invention and related specifications are included. An acknowledgment of this report can be found in Daniels's letter of April 4, 1917, in Report 24.

This project is described on p. 192 of Lloyd N. Scott's Naval Consulting Board of the United States.