The unbound correspondence, trade circulars, and other loose documents in this subseries relate to the purchase of equipment and supplies for the West Orange laboratory and other Edison interests. Many of the documents are unsolicited promotional circulars or routine letters involving the specifications, availability, cost, and delivery of equipment and supplies. Included are memoranda asking that materials be ordered; requests for prices or samples; and letters acknowledging orders from, or shipments to and among, Edison's interests. Orders for equipment, supplies, and foundry work often include requisition numbers, voucher numbers, or laboratory project numbers indicating the experiment or the Edison company to be billed for the order. In most cases the information or materials were requested on Edison's behalf by members of his laboratory staff, including Alvin D. Caskey, Fred C. Devonald, and Frederick P. Ott. Some of the outgoing and incoming letters involve the work of Henry J. Harms, Jr., and George E. Small on Edison's concrete house. A small group of items indicates Edison's direct oversight of individual requests or purchases.

Less than 5 percent of the documents have been selected. In general, only items that indicate Edison's direct participation in the order, purchase, and receipt of equipment and supplies have been selected. Also included are several of the Harms and Small letters and a list of chemicals sent to the laboratory from the defunct New Jersey and Pennsylvania Concentrating Works in Ogden, New Jersey. Related documents that provide an overview of laboratory purchases and expenditures may be found in the laboratory account books.