This notebook covers the period December 1878-January 1879. Most of the entries are by Francis Upton. A few are by Charles Batchelor. All of the material relates to experiments on electric lighting. Included are notes and calculations on filament experiments; notes, drawings, and calculations on generators; and calculations on electric power distribution systems, with comparisons to gas lighting. On page 198 is a table on the cost of electric light, calculated for varying numbers of lamps per day, month, and year. The book contains 284 numbered pages.

Blank pages: 46-47, 260-261.

Courtesy of Thomas Edison National Historical Park.