This notebook contains only a few dated entries, covering the period March 1874-January 1875. Most of the entries are by Charles Batchelor and are primarily calculations and drawings of component parts of instruments relating to the domestic, automatic, and printing telegraph systems. In the middle of the volume are blue stains, apparently made by the discs used in Edison's recording telegraphs. A list of six names and addresses can be found near the end of the volume. The cover is labeled "Vol.5." The book contains approximately 200 unnumbered pages. Many leaves have been torn out.