Restricted for 15 years; until Jan-01-2021. Copyrighted material in Box 3 (Mineral Technology: Myles Salt Company, 1916; and John N. Hoffman: "Study of Surface Mine Refuse Fires," Pennsylvania State College, 1949-1950); see finding aid. Transferring office; 5/8/1997 memorandum, Johnstone to Langley; Contact reference staff for details.
Collection Citation:
Smithsonian Institution Archives, Accession 20-134, National Museum of American History. Division of the History of Technology, Curatorial Records
