This folder contains correspondence and other documents relating to Edison's search for an inexpensive supply of cobalt ore for possible use in the alkaline storage battery. Included are letters and shipping receipts received from field workers R. D. Casterline, John Morris, and others, whom Edison sent to Tennessee, North Carolina, and elsewhere.

Less than 5 percent of the documents have been selected. These consist of samples of the letters from Casterline and Morris, along with Edison's notes and telegrams to field workers.