These two letters are from Edison to John P. Sanborn, a U.S. Customs Collector and a founder of the City Railroad Co. of Port Huron, Michigan. A letter from December 1876 concerns the merger of Sanborn's company with the Port Huron and Gratiot Street Railway, a company owned and managed by Edison's older brother William Pitt Edison, in which the younger Edison owned stock. In 1877 the investors consolidated the two lines into the Port Huron Railway Co. and elected Sanborn as president and William Pitt Edison as superintendent. The second letter, which possibly dates from 1880, involves the appointment of a successor to William Pitt Edison.
[X056AA], Letter from Thomas Alva Edison to John P Sanborn, December 27th, 1876 1876-12-27
[X056AB], Letter from Thomas Alva Edison to John P Sanborn, 1880 1880-00-00