  Precision measurements of the inverse-square law via experiments on
short-range gravity provide sensitive tests of Lorentz symmetry. A combined
analysis of data from experiments at the Huazhong University of Science and
Technology and Indiana University sets simultaneous limits on all 22
coefficients for Lorentz violation correcting the Newton force law as the
inverse sixth power of distance. Results are consistent with no effect at the
level of $10^{-12}$ m$^{4}$.
