This letterbook covers the period April-July 1891. Most of the correspondence is by Thomas Butler, secretary of the company, and William S. Perry, treasurer. Some of the letters are by Samuel Insull, vice president. The letters deal mainly with orders for ore concentrate, leases on mining property, and stock transactions. Some letters pertain to the disposition of property at the Bechtelsville mill, while others concern the acquisition of the Ogden Iron Co. A few items relate to the hiring of Henry W. Hart as general manager following the resignation of Harry M. Livor. The spine is marked "C." The book contains 998 numbered pages and an index of recipients and subjects. Approximately 5 percent of the book has been selected. Most of the letters are written in very faint green ink and may be difficult to read.