This notebook covers the period January 1890-March 1891. All entries are by Edison. The book contains notes relating to numerous mines and methods of ore separation for iron, copper, gold, and nickel. Also included are drawings regarding phonographs, generators, and electrical distribution systems. Near the end of the book are cost calculations for the North American Phonograph Co. The front cover is labeled \"#582.\"" The inside front cover is inscribed \""#582 T A Edison Jan 4. 90.\"" The pages are unnumbered. Approximately 110 pages have been used."