Let K be a compact set in a
Euclidean space and let d be a metric on K which is continuous with respect to the
usual topology. The generalized energy integral I(μ) =∫∫d(x,y)dμ(x)dμ(y) is
investigated as μ is allowed to range over the lamily of signed Borel measures of total
mass one concentrated on K. A trick of integral geometry is used to define a class of
metrics d, including many standard ones, possessing a number of pleasing properties
related to the functional I.