"Some physicists think that a fifth force of nature due to hypercharge may have been found by the Eotvos experiments." See Ephraim Fischbach et al, Reanalysis of the Eotvos Experiment, Physical Review Letters, 56(1), Jan. 6, 1986, p. 3-6. (Bearden, Thomas E.; Analysis of Scalar/Electromagnetic Technology; Tesla Book Company; P. O. Box 121873, Chula Vista, CA 91912)
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