  In this talk I will describe some recent results on the sensitivity of
resonant mass detectors shaped as a hollow sphere to scalar gravitational
radiation. Detection of this type of gravitational radiation will signal
deviations from Einstein's gravity at large distances. I will then discuss a
class of experiments aiming at finding deviations from Einstein's gravity at
distances below 1 cm. I will review the main experimental difficulties in
performing such experiments and evaluate the effects to be taken in account.
