This notebook covers the period June 1879-April 1880. Most of the entries are by Francis Upton. There are also a few entries by Edison and John Kruesi. The entries by Upton consist of notes, calculations, and drawings relating to generators and electric power distribution, including costs. The entries by Edison include a "law" about the strength of dynamo machines and notes and drawings of chalks for the telephone. The entries by Kruesi consist of notes, calculations and drawings relating to the construction of dynamo machines. The label on the front cover is marked "Regulator" and "transmission." The book contains 282 numbered pages.

Blank pages: 56-57, 234-281.

Missing page numbers: 157-158, 231-232.