Copy letter from Robert William Frederick Harrison, to Professor Dr H Griesbach, 29 Industrie Strasse, Mulhausen, Elsass, Germany 'Dear Sir, In reply to your card of Feb. 24, I cannot give you any information concerning Wrench, the inventor of the metal-thermometer. I am, with regret, yours faithfully, Robt Harrison Asst. Sec. R.S. [Assistant Secretary of the Royal Society]'. 3 March 1899