This letterbook covers the period December 1891-November 1892. Most of the correspondence is by William S. Perry, treasurer; Charles Batchelor, general manager; and Thomas Butler, secretary. The letters deal mainly with capital calls, annual reports, announcements of meetings, purchases of equipment and supplies, leases, and royalties. Other items pertain to progress at the New Jersey and Pennsylvania Concentrating Works in Ogden, N.J. One letter mentions Edison's disposition during a meeting with William S. Perry. The spine is stamped "Letters to N.Y.C. 3" The book contains 988 pages and an index (not selected). Pages 446-988 are blank. Less than 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.