This folder contains correspondence and other documents pertaining to the procurement and testing of batteries. Some of the letters deal with batteries for the phonograph and phonoplex. Related documents can be found in D-90-27 (Edison Manufacturing Co.).
Approximately 90 percent of the documents have been selected. Most of the documents not selected concern G. W. Ladd's battery work. Also not selected are duplicate copies of selected documents. Courtesy of Thomas Edison National Historical Park.