Coal. Constitutionality of bituminous coal conservation act of 1935, opinion, with separate and dissenting opinions in cases of James Walter Carter v. Carter Coal Co., George L. Carter, as vice president and director of said company, et al.; Guy T. Helvering et al. v. James Walter Carter et al.; R. C. Tway Coal Co. et al. v. Selden R. Glenn, individually and as collector of internal revenue for district of Kentucky; R. C. Tway Coal Co., R. C. Tway, president; and directors of R. C. Tway Coal Co., et al. v. C. H. Clark, involving constitutionality of bituminous coal conservation act of 1935; presented by Mr. Guffey.