Letter from Sir Henry Dale, President of the Royal Society, to Sir Harold Hartley, Watford, Hertshire Is sorry to hear of Hartley's illness - hopes that he will still be able to give the Lavoisier Lecture on 14 October, but could have it changed to 4 November. Read Hartley's article in the 'Times' and asks how Lavoisier's central discovery relates to Lavoisier's experiments 'made at the Tower' on the weights of bodies increased in the fire. 4 September 1943