This pocket notebook from box 20 (Series 1) of the William J. Hammer Collection was used by Hammer in his capacity as chief engineer of Edison's demonstration central station at the Holborn Viaduct in London. It is a record of his activities and expenses, beginning with his arrival in October 1881 and continuing through May 1882. An inscription at the beginning of the book reads: "Notes re building, starting and early operating of 1st Central Station in the world. Holborn Viaduct London, England by Wm. J. Hammer Chief Engineer." The pages are unnumbered; approximately 120 pages have been used.

Courtesy of the NMAH Archives Center.