of uncertainties as to post—war world demands, rate of mine production, U.S.A domestic subsidies, and the fact that whereas before the war it was self- contained or an exporter of copper, lead and zinc, the U.S.A. will probably in future be a substantial importer. 4. The present position as regards the various metals is as follows;- Copper The anticipated surplus has not appeared. For various reasons, including the switch from production to development at mines, production has fallen much more sharply than expected; the U.