That recognition of self-sufficiency problems has become increasingly widespread has been evinced by numerous publications, by plans and legislation designed to correct any deficiencies in American supplies. Stock-piling for accumulation of reserves of deficiency materials, encouragement of domestic developments, and abatement of exports of essential materials have been principal objectives of nearly all plans and legislation suggested. Of the books, monographs, reports, and articles treating the general subject of raw material deficiencies, none had approached the subject so geographically as did Hall in an article in the Geo-