Because of equivalence of mass and energy Heim says there must also exist a field mass of the field energy of each field. However in case of gravitational field this results in a secondary (very weak) additional gravitative source because a field mass possesses its own gravitational field.
In a volume V0 there is mass which may be distributed in
any kind. This mass is producing a gravitation effect, as it can be
described with Newton's approximation (yellow level). Now Heim says
that to the energy of this gravitational field corresponds its own field
mass (blue level). This field mass again produces a second additionally
gravitational field which is very weak (highest level).
Again this field possesses its own field mass which produces a field. So
you receive an infinite series, which however converges
very fast against a calculable limit value.
The whole description results in a short mathematical description for
a corrected gravitation law, which corresponds with
Newton's gravitation law within the observable area of space.
However for very large distances it will provide completely different
results. As you can see in the illustration below for very long
distances gravition will produce a weak repulsing force
wich will only exist if a mass is moving toward the centre of the
gravitational field. Among other things the phenomenon of the cosmic red
shift can be explained now as a gravitational effect.
The field process and some consequences of the corrected gravitation law are described at the next page.