This journal covers the period January 1, 1877-April 8, 1878 and contains entries by Batchelor about his experiments on the electric pen, phonograph, and telephone. Other entries deal with the quadruplex telegraph and Batchelor's personal affairs. The book contains 365 pages, numbered by an archivist. After writing the entry for December 31, 1877, Batchelor returned to the first page of the book and began recording entries for 1878. Pages 1-98 (January 1-April 8) thus contain entries for both 1877 and 1878. The front cover is stamped "Diary 1877." Courtesy of Thomas Edison National Historical Park.