Letter from W [William] Ramsay, 19 Chester Terrace, Regent's Park, to [Joseph] Larmor He thinks it would not be possible in [Ernst Hendrik] Buchner's case to test for a charge as the powdered mineral lay on a copper disc at the bottom of the earthed electroscope. Ramsay notes independent evidence in the experiments of one of his students, Spencer, who is studying relative rates of discharge of an electroscope caused by reflecting ultraviolet light onto the disc. The rate of discharge is retarded by sulphur, but other things accelerate. Ramsay does not think there is a mistake, but cannot account for the effect. 28 March 1906