This notebook covers the period July-August 1905. There is also one dated entry from January 1906. All entries are by Edison. The book contains notes regarding the search for sources of cobalt, which Edison tested as a component of his alkaline storage battery. Included are survey notes of numerous North American mines, along with records of cobalt ore separation experiments. Near the end of the book is a list of battery experiments to be performed. The front cover is labeled \"Cobalt.\"" The pages are unnumbered. Approximately 90 pages have been used.