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Two generally covariant integral conservation laws concerning electromagnetic null fields and vacuum gravitational fields of type II with vanishing Riemanneigenvalue respectively are proved. The conserved quantities both have the dimensions of action. The electromagnetic law shows that with respect to the propagation of energy a null field may be represented by a stream of photons. The gravitational conservation theorem is in many respects similar to the electromagnetic one; it admits to calculate the change of intensity along a gravitational ray

Erhaltungss�tze f�r die Wirkung in elektromagnetischen und gravischen Strahlungsfeldern