This folder contains correspondence and other documents relating to Edison's search for an inexpensive supply of cobalt ore for possible use in his alkaline storage battery. Included is correspondence with the North American Lead Co., the Standard Consolidated Mines Co., and other possible suppliers of cobalt ores from Oregon, North Carolina, Canada, and New Caledonia. Several items, including a long memorandum in Edison's hand and a two-page typewritten itinerary, pertain to Edison's prospecting trip to North Carolina in May and June. Related material can be found in the records of the Mining Exploration Company of New Jersey in the Company Records Series.

Approximately 50 percent of the documents have been selected, including samples of items bearing Edison marginalia. Among the items not selected are letters from companies and individuals seeking to interest Edison in various propositions for mining, assaying, or processing cobalt ores; letters replying to Edison's requests for geological survey maps and other general information; letters of acknowledgment; and documents that duplicate information in selected material.