[en] It is proposed that the spin polarization of delta electrons should be used as a measure of the strong magnetic fields (B approximately 1017 G) induced by the nuclear motion in collisions of very heavy ions. The polarization is typically of the order of 10-20 percent in Pb-Pb and U-U collisions. The authors also discuss the bombarding energy dependence up to Esub(lab) = 200 MeV/u, where 500 keV level splitting between spin up and down states is obtained. (Auth.)