This notebook is undated but was probably used in 1880 or 1881. There are entries by Edison and probably by Charles P. Mott. The material was copied from other notebooks, which were probably used in patent interference cases. A number of entries give references to specific interference cases. Included are notes and drawings of carbon filament lamps, vacuum pumps, and dynamos. In some cases, a date has been assigned to material that was not dated in the original notebook. The book contains 284 numbered pages.

Blank pages: 18-19, 46-47, 78-79, 110-111, 142-284.

Missing page numbers: 129-130.