In National Labor Relations Board v. Pennsylvania Greyhound Lines, Inc., 303 U.S. 261, 58 S.Ct. 571, 572, 82 L.Ed. 831, 115 A.L.R. 307, three related corporations were involved. The two respondents claimed that the third corporation was the `employer'.
In N.L.R.B. v. Sands Mfg. Co., 306 U.S. 332, 59 S.Ct. 508, 83 L.Ed. 682, affirming the ruling of this Court in 6 Cir., 96 F.2d 721, the Supreme Court held the employer justified in abandoning further negotiations with the Union when conditions showed the uselessness of continuing with them.