This is the last of six pocket notebooks used by Charles P. Mott, a member of the office staff at Menlo Park, to record daily activities at the laboratory. The entries from these notebooks were used as the basis for more extensive entries recorded by Mott in Menlo Park Notebooks #53 and #117. The entries in this pocket notebook, which covers the period January-March 1881, continue beyond the entries in Menlo Park Notebook #117, which ends in January 1881. The front cover is labeled "155" and is inscribed "C. P. Mott Jany 19.81" and "6." The pages are unnumbered. Approximately 50 pages have been used.