No. 21375. Argued May 24, 1968. Decided July 3, 1968. Mr. Philip P. Ardery, Lousville, Ky., for petitioner. Mr. Israel Convisser, Attorney, Federal Power Commission, with whom Messrs. Richard A. Solomon, General Counsel, and Peter H. Schiff, Solicitor, Federal Power Commission, were on the brief, for respondent. Mr. Malcolm Y. Marshall, Louisville, Ky., with whom Mr. Squire R. Ogden, Louisville, Ky., was on the brief, for intervenor. Mr. Thomas M. Debevoise, Washington, D.C., also entered an appearance