These documents cover the years 1899-1924. Much of the correspondence relates to the financial and legal affairs of the Edison Portland Cement Co., including the issuance and transfer of stock and the assignment of patents. Other letters concern electroplating experiments. Among the correspondents are Edison; William Walter Dinwiddie, a laboratory engineer; Frank L. Dyer, Edison's general counsel; Halbert K. Hitchcock, Edison's brother-in-law and president of the Pittsburgh Plate Glass Co.; and William H. Meadowcroft, Edison's personal assistant. Courtesy of the Wichita State University Libraries.