  X-ray resonant scattering at the K-edge of transition metal oxides is shown
to measure the orbital order parameter, supposed to accompany magnetic ordering
in some cases. Virtual transitions to the 3d-orbitals are quadrupolar in
general. In cases with no inversion symmetry, such as V$_2$O$_3$, treated in
detail here, a dipole component enhances the resonance. Hence, we argue that
the detailed structure of orbital order in V$_2$O$_3$ is experimentally
accessible.
