This notebook covers the period October 1885-November 1886. Most of the entries are by Edison. Included are notes and drawings relating to the telephone and phonoplex, electric power distribution, lamp experiments, a thermostatic regulator for heating houses, a kerosene lamp for railroads, and a snow clearing machine. There are also measurements, calculations, and tables labeled "horizontal force"; notes on thermoelectricity; building plans for a new laboratory; and a list of items wanted by the Railway Telegraph and Telephone Co. A few entries on the telephone and phonoplex are by John F. Ott, one entry on the telephone is by Ezra T. Gilliland, and one entry on the phonoplex appears to be by Alfred O. Tate. Many of the entries were witnessed by Ott and Martin Force. The inside front cover was signed by Samuel Edison. The book contains 280 numbered pages.

Blank pages: 70-75, 90-91, 122-123, 152-153, 168-173, 176-181, 204-209, 234-235, 244, 247, 268, 271.

Missing page numbers: 133-136, 213-222, 227-232, 245-246, 251-264, 269-270, 277-278.