[The following pocket notebook was discovered after the microfilm edition of Thomas A. Edison Papers, Part I (1850-1878) was published and was initially published in the Supplement Series in the microfilm edition of Thomas A. Edison Papers, Part III (1887-1898). To see the location of this item in the Series Notes for Part I, use the "Which Series Notes?" button.]

This undated pocket notebook is the second of two books that were probably used by Edison in January 1871. Most of the entries relate to automatic telegraphy, particularly the design of an electric perforator. In addition, there are several miscellaneous drawings and calculations. The cover is missing. The pages are unnumbered, and several pages have been torn from the book. Approximately 25 pages have been used.