  A complete set of wave solutions is given for the weak field in a
Kaluza-Klein theory with degenerate metric. In the five-dimensional version of
this theory electromagnetism is described by two vector fields, and there is a
reflection symmetry between them which unifies them with gravitation; wave
behaviour in the extra dimension has been interpreted as dark matter. Here
three independent dark matter solutions are found, and for two of them it is
shown how they must be combined into a single solution in order to obey the
reflection symmetry. The unification is also expanded to six dimensions to
prepare the way to include further forces.
