Engineer Notebooks 1900-1922
The engineer assigned to each harbor defense kept a notebook on the defense structures that were located in a given harbor defense. They maintained a ledger, a journal, and memorandum log for the batteries, the fire control structures, the electrical generators, the searchlights, the torpedo (mine) structures, and in some cases, the land defenses. A fairly complete set appears to have been collected around the mid-1920s and is now housed in the National Archives. These notebooks have information on when the structures were built, but more importantly information on modifications and changes to these structures over the years. The CDSG ePress has a series of PDF files that have been copied from the National Archives.