No. 6582. Argued June 24, 1953. Decided July 13, 1953. Owsley Vose, Atty., National Labor Relations Board, Washington, D.C. (George J. Bott, Gen. Counsel, David P. Findling, Associate Gen. Counsel, A. Norman Somers, Asst. Gen. Counsel, and Rose Mary Filipowicz, Atty., National Labor Relations Board, Washington, D.C., on the brief), for petitioner. Harold R. Schmidt, Pittsburgh, Pa. (Thomas G. Shufflebarger, Richlands, Va., Jacob M. Murdock, John L. Laubach, Jr., and Rose, Rose Houston, Pittsburgh