This notebook covers the period January-May 1899. It has been used in both directions. At one end is a series of unnumbered pages containing notes and drawings by Edison relating to tests of an electrolytic meter. At the other end are numbered and unnumbered pages containing entries by Edison and his associate Francis R. Upton regarding the crushing of cement rock. The book contains 121 numbered pages, some of which are blank, and approximately 60 unnumbered pages.