This notebook covers the period December 1885-July 1886. There is also one entry from September 1888. All of the entries are by Edison except for one entry by an unknown assistant. Included are notes and drawings relating to armature windings and non-sparking commutators, engines and boilers for central station plants, lamp experiments, electric power distribution systems, and the phonograph. On page 290 is a list by Edison of competing electric light companies. The book contains 292 numbered pages.

Blank pages: 16-17, 26-29, 58-59, 72-73, 76-77, 228-237.

Missing page numbers: 1-2, 61-62, 79-102, 113-164, 203-212, 217-218, 239-252, 267-284.