Measurements of a Machian transient mass fluctuation

The prediction of a novel transient mass fluctuation expected in relativistic theories of gravitation that satisfy the globally-local Mach condition (that the cosmic gravitational potential is roughly equal to the square of the speed of light) is set forth. Cosmological consequences of the Mach condition are mentioned, and an experiment that tests the prediction is discussed. The apparatus, procedure, and results of this experiment are described. The predicted effect is seen with better than order of magnitude accuracy.