  For a certain class of configurations of points in space, Eves' Theorem gives
a ratio of products of distances that is invariant under projective
transformations, generalizing the cross-ratio for four points on a line. We
give a generalization of Eves' theorem, which applies to a larger class of
configurations and gives an invariant with values in a weighted projective
space. We also show how the complex version of the invariant can be determined
from classically known ratios of products of determinants, while the real
version of the invariant can distinguish between configurations that the
classical invariants cannot.
