  Years ago Edwards proposed a thermodynamic description of dense granular
matter, in which the grains (the `atoms' of the system) interact with inelastic
forces. The approach is intriguing but is not justified from first principles,
and hence, in the absence of conclusive tests of its validity, it has not been
widely accepted. We perform a numerical experiment with a realistic granular
matter model specially conceived to be reproducible in the laboratory. The
results strongly support the thermodynamic picture.
