The results of two years of operation of a 1660-cps gravitational-wave detector are reviewed. The possibility that some gravitational signals may have been observed cannot completely be ruled out. New gravimeter-noise data enable us to place low limits on gravitational radiation in the vicinity of the earth's normal modes near one cycle per hour, implying an energy-density limit over a given detection mode smaller than that needed to provide a closed universe.

• Received 8 February 1967

DOI:https://doi.org/10.1103/PhysRevLett.18.498