This notebook covers the period January 1880-January 1881. Most of the entries are by Albert B. Herrick. There are also a few entries by other laboratory assistants. The first part of the book contains a record of street lamps at Menlo Park during January 1880. Following this are many pages of miscellaneous calculations along with a few drawings of lamps, generators, and other devices; notes on chalk cylinders; and drawings and dimensions of a Porter-Allen high-speed engine. There are also three draft letters by Herrick, two relating to telephone orders and installations and one about a vacuum pump order. The label on the front cover is marked "Herrick." The first page is inscribed: "Sworn in Evidence Ashcroft - Justice Peace NY City." The book contains 282 numbered pages and has been used in both directions. The pagination is irregular; some numbers are used for more than one page.

The notebook pages appear in the following order: pp.1-243, 282-260 [in reverse page-number order].

Blank pages: 172-173, 176-177, 184-185, 218-233, 238-241, 244-259.

Missing page numbers: 201-202, 247-248.

Courtesy of Thomas Edison National Historical Park.