Letter from JD Roberton, Royal Society, to Sir John Herschel On the referral to Herschel of a paper by James D Forbes. Herschel was asked to judge whether the paper was suitable to be awarded the Royal Society's Gold Medal. The paper in question ("On the Transparency of the Atmosphere and the Law of Extinction of the Solar Rays in Passing through It") was the Bakerian Lecture of 1842. 3 November 1843