Copy letter from Robert William Frederick Harrison to W Geoffrey Duffield, Physical Laboratories, Physical Laboratories, The University, Manchester 'Dear Sir, In reply to your letter to Sir Joseph Larmor, I have to inform you that your paper was safely received here. It is the custom of the Society to acknowledge the receipt of papers to the Communicators, and not to the Authors. I note the the "Summary of Results" at the end of your paper is to be used as the Abstract.' 12 May 1910