  String theory, as well as the string inspired brane-world models such as the
Randall-Sundrum (RS) one, suggest a modification of Newton's law of gravitation
at small distance scales. Search for modifications of standard gravity is an
active field of research in this context. It is well known that short range
corrections to gravity would violate the Newton-Birkhoff theorem. Based on
calculations of RS type non-Newtonian forces for finite size spherical bodies,
we propose a torsion balance based experiment to search for the effects of
violation of this celebrated theorem valid in Newtonian gravity as well as the
general theory of relativity. We explain the main principle behind the
experiment and provide detailed calculations suggesting optimum values of the
parameters of the experiment. The projected sensitivity is sufficient to probe
the Randall-Sundrum parameter up to 10 microns.
