American Silver Producers Association. No. 153, in Supreme Court, Oct. term 1929, United States ex rel. American Silver Producers Association, Delia S. Consolidated Mines Company, and Spar Consolidated Mines Company, v. Andrew W. Mellon, Secretary of Treasury, and Robert J. Grant, director of mint, on petition for writ of certiorari to Court of Appeals of District of Columbia; brief for respondents in opposition.