  It is shown that in the weak field approximation the new geometrical approach
can lead to the linear field equations for the several independent fields. For
the stronger fields and in the second order approximation the field equations
become non-linear, and the fields become dependent. This breaks the
superposition principle for every separate field and produces the interaction
between different fields.The unification of the gravitational and
electromagnetic field theories is performed in frames of the geometrical
approach in the pseudo Riemannian space and in the curved Berwald-Moor space.
