Copy letter from Robert William Frederick Harrison, to Rollo Appleyard 'Dear Sir, I have your letter of the 23rd April and thank you for your offer to exhibit the conductometer at the May Soirée. I regret, however, that we have now no space available to offer you, but perhaps I could arrange for you to exhibit it at the Soirée in June, if you are willing to do so then. I am, Dear Sir, faithfully yours, Robt [Robert] Harrison Asst. Sec. R.S. [Assistant Secretary, Royal Society]'. 29 April 1904