This notebook covers the period June 1879-September 1880. The entries are by Edison, Charles Batchelor, John Kruesi, and Francis Upton. Most of the material relates to electric light or telephone experiments. The electric light material includes notes, calculations, and drawings of generators; drawings of filaments, bulbs, and sockets; and notes on equipping the Menlo Park lamp factory. The telephone material includes notes and drawings relating to telephones, central exchange systems, and chalk experiments. There are also notes on ore separation and notes and drawings of the electric railroad. The book contains 282 numbered pages.

Blank pages: 60-63, 94-95, 114-117, 134-135, 188-189, 198-199, 206-243, 246-247, 250-255, 258-261, 266-269, 272-273, 276-279.

Missing page numbers: 165-166.