Search for a substance-dependent force with a new differential accelerometer

A well-balanced hollow copper sphere freely floating and almost totally submerged in water is observed to move toward the nearby edge of a cliff. This observation is consistent with a substance-dependent, medium-range force postulated in a recent reanalysis of the Eötvös experiment. Further measurements with different elements and geometries will be required to establish definitely the existence, source, and description of such a new force.