The two dated entries in this notebook are from November 1889 and September 1891. The book was used by John Ott for notes and a drawing regarding an "Experiment on Chemical Engin[e] for Phonograph." There are also several drawings relating to lamp and transformer experiments, and one newspaper clipping on the Baldwin Locomotive Works. The spine is labeled "100." The pages are unnumbered. Approximately 30 pages have been used.