A non-relativistic theory, especially of mass

The idea, to consider the energy constancy as an absolute one, as well as an analogy to the tentative hypothesis, the optical dense medium to be a small mass atmosphere around all material bodies, are presented in order to avoid the inconsistency between the regularities of electromagnetic waves on the one hand and the de Broglie waves of material particles on the other hand. Consequences for motions near the earth and in the immediate neighbourhood of our sun are discussed. An interpretation of the missing-mass phenomenon in astronomy by a gravitational ether of potential energy is given. Reservations concerning Einstein's general theory of relativity are advanced based on the doubt about the defensibility of the equivalence - principle of gravity and inertia