 For nearly 20 years, starting in the early 1960s, Allen collaborated with Erwin Saxl, an industrial physicist living in Harvard, Massachusetts, on experiments with a torsion pendulum.Allen and Saxl reported anomalous changes in the period of a torsion pendulum during a solar eclipse in 1970 and hypothesized that “gravitational theory needs to be modified”.Their measurements, and similar anomalies earlier observed by Allais using a paraconical pendulum, have not been accepted by the physics community as in need of unconventional explanation, and subsequent experiments have not succeeded in reproducing the results.