This notebook covers the period July 1880-February 1881. All of the entries are by Francis Jehl except for one drawing by Edison of a lamp with a spark gauge. Included are notes, calculations, and drawings of lamp and vacuum pump experiments; notes on motor and dynamo experiments; and notes and calculations about meter experiments. There are also notes and calculations relating to battery tests, resistance tests for wire and electric railroad track, tests of copper wire, and tests of insulation compounds. The label on the front cover is marked "Francis Jehl" and "1880." An index has been pasted onto the inside front cover. The book contains 284 numbered pages.
Blank pages: 202-203, 216-221, 224-229, 248-249, 260-261, 264-269, 274-275. Courtesy of Thomas Edison National Historical Park.