Experimental Test of the Freundlich Red-Shift Hypothesis

An experiment to test the Freundlich photon-scattering hypothesis, which was designed to explain the Hubble cosmological red shift, is described. Laser light is passed through an rf cavity placed in one arm of an interferometer sensitive to 10^-8 fringe shift. The experiment sets a limit of Δνν<10^-18 on the frequency shift of 6328-Å photons passing through 2 m of X-band radiation field with an energy density of 2 erg/cm³.