Henry Cavendish, John von Soldner, and the deflection of light, Clifford M. Will, Am. J. Phys. 56(56), May 1988
The gravitational deflection of light based on Newtonian theory and the corpuscular theory of light was calculated, but never published, around 1784 by Henry Cavendish, almost 20 years earlier than the first published calculation by Johan Georg von Soldner. The two results are slightly different because, while Cavendish treated a light ray emitted from infinity, von Soldner treated a light ray emitted from the surface of the gravitating body. At the first order approximation, they agree with each other; both are one-half the value predicted by general relativity and confirmed by experiment.