[The following note describes a series of volumes and has no documents attached to it. For that reason, a "no Documents found" message will appear if the "List Documents" button at the bottom of the note is used. To see the documents in the volumes described here, use the "Which Series Notes?" button to enter the Series Notes or use the "Next Text" button to move to the first item in the series.]
The Menlo Park Notebooks cover the period 1878 to 1882. Some of the books also contain entries from 1883, 1884, and 1885. These books are the principal sources for documenting the invention and development of Edison's system of electric lighting and power. They also contain much material on the telephone, as well as scattered entries detailing work on electric railways, batteries, ore separation, telegraphy, and various other technologies. The books generated during the first year of work on the electric light are primarily by Edison, Charles Batchelor, and Francis Upton. The names of other laboratory assistants frequently appear as witnesses. As the staff of the laboratory expanded, many other individuals began making entries in the notebooks.
The Menlo Park notebooks are numbered from 1 to 249. Approximately 70 books are missing from the set. Pasted onto the inside front cover of many of the Menlo Park notebooks is a bookplate with the inscription: "Library of the Board of Patent Control, 120 Broadway, New York. May 1, 1896." The words "General Electric" have been crossed out and the following notation added in red ink: "From Library 44 Broad St., N.Y.C." Many of these notebooks also contain labels tipped into various pages, describing the experiments that follow. These labels often enumerate patents relating to these entries or suggest that the entries were ''unimportant'' for defending patent claims.
All of the extant notebooks have been selected with the exception of a few books that contain mathematical calculations without accompanying notes and drawings or that relate to routine shipping transactions. The books are arranged in the order of their Menlo Park number.
Initially, it was the practice for members of the laboratory staff to sign and date each notebook entry. However, as the press of work and the size of the staff increased, Edison and his associates sometimes neglected to sign and date their work. As a result, there are many notebooks containing only a few dated entries, and some of the books are entirely undated. There are several methods of assigning dates or date ranges to undated notebook entries. Sometimes two members of the staff recorded the same set of experiments in separate notebooks. In such cases, an undated set of notes in one book may be dated in the other book. Date ranges can be assigned to other undated entries by a careful examination of dated entries on the pages preceding and following the undated entry. Moreover, it is usually possible to determine the earliest date that a particular notebook could have been used by examining the cover of the book. The earliest Menlo Park notebooks (November 1878-April 1879) all have blue-green covers. The covers of the later notebooks are a variety of colors, including dark red, light blue and black, dark blue and black, and green-orange. An analysis of the notebooks with dated entries reveals that books with similar covers were usually generated during the same time period. Thus, it is possible to conjecture that an undated notebook with a light blue-black cover dates from the period April-December 1880 and that a notebook with a dark blue-black cover dates from the period after January 1881.
One other source is invaluable for dating notebook entries from 1880. There are two Menlo Park Notebooks and six pocket notebooks that were used by Charles P. Mott, a member of the Menlo Park office staff, to record the daily activities of the laboratory between March 1880 and March 1881. Mott sometimes included references to specific notebooks and mentioned the names of individuals working on specific projects, thus allowing the attribution of authors and dates to entries that could otherwise only be conjectured.
For the early books, which are primarily by Edison, Charles Batchelor, and Francis Upton, it is usually possible for a careful researcher to distinguish writing and drawing styles in cases where an entry is unsigned or more than one person signed the entry. For the later books it is more difficult to attribute authorship, but the Mott journals can help the researcher become familiar with the writing and drawing styles of the various staff members.
A more extended discussions of these issues can be found in Robert Freidel and Paul Israel, Edison's Electric Light: Biography of an Invention (New Brunswick: Rutgers University Press, 1986), 233-238.