This notebook covers the period March-June 1879. Most of the entries are by Edison and Charles Batchelor. There are also entries by Francis Upton and John Kruesi. All of the material relates to either electric lighting or the telephone. The electric light material includes notes on coatings for metal filaments; drawings of lamps; notes, drawings, and calculations about generators; and drawings and calculations about electric power distribution. The telephone material includes notes, drawings, and tests of the electromotograph receiver; notes and drawings of a central telephone exchange system; and notes on parts and prices of telephones. The book contains 284 numbered pages.

Blank pages: 110-Ill, 146-147, 152-153, 170-189, 206-207, 210-217, 220-225, 252-281.