Copy letter from Robert William Frederick Harrison to Dr H [Hans] F [Friedrich] Gadow FRS 'Dear Dr Gadow, We are trying to arrange suitable exhibits and demonstrations for the Soiree on May 12, and it has been suggested that you might be willing to give a short discourse with illustrations in the Meeting room in the course of the evening.If you have material for such a demonstration it would undoubtedly prove very attractive, and I shall be much obliged by your letting me know as soon as possible whether you have such material and are prepared to entertain the idea.' 5 April 1909