This undated notebook was probably used sometime during the period 1901-1904, although the entries at the end of the book may have been added at a later date. All entries are by Edison. The book contains notes and drawings regarding storage battery experiments, including a list of possible explanations for low power output from the cells and a set of cost calculations for a competitor's automobile battery. There are also entries describing various methods for electrochemically extracting silver from nickel-cobalt ores. Near the end of the book are several drawings that could be preliminary sketches for Edison's concrete houses. The front cover is labeled "Very Important." The pages are unnumbered, and several pages have been removed from the book. Approximately 140 pages have been used.