This undated notebook was used by Edison, probably during the period 1899-1901. It has been used in both directions. Beginning at one end are notes, drawings, and calculations regarding ore milling and storage battery experiments, particularly a copper-zinc cell. At the other end are notes and drawings relating to the use of Edison's ore milling technology in the production of phosphates and phosphoric acid. The book contains 137 numbered pages followed by approximately 20 unnumbered pages. Some pages are blank; pages 3-8 and 13-14 have been removed from the book.