*726Appeal from the United States District Court for the Northern District of Illinois. Probable jurisdiction noted.
Solicitor General Rankin, Acting Assistant Attorney General Bicks, Philip Elman, John F. Davis and Charles H. Weston for the United States.
John Lord O’Brian, Hugh B. Cox, Charles A. Horsky and Daniel M. Gribbon for E. I. du Pont de Nemours and Co., Leo F. Tierney, Robert L. Stern, Henry M. Hogan and Robert A. Nitschke for General Motors Corp., Wilkie Bushby and Philip C. Scott for Christiana Securities Co. et al., appellees.