This folder contains correspondence relating to the technical and commercial development of Portland cement. Also included are documents pertaining to Edison's interest in promoting the use of pulverized limestone for soil conditioning. The incoming letters bear comments by Edison regarding the manufacture and sale of cement, the use of steel-reinforced concrete, and the construction of buildings at the West Orange laboratory. There are also references to his promotion of electric vehicles. Among the correspondents are George F. Randolph of the Baltimore & Ohio Railroad Co., E. B. Thomas of the Lehigh Valley Railroad Co., and Frederick D. Underwood of the Erie Railroad Co. A communication from H. H. Meno Kammerhoff concerning the development of small motors for use in drying tunnels possibly refers to plant operations at the Edison Portland Cement Co.

Approximately 60 percent of the documents have been selected. The items not selected consist primarily of unsolicited correspondence that received no reply or only a perfunctory response from Edison.