Copy letter from Robert William Frederick Harrison to Professor H [Hugh] L [Longbourne] Callendar, Fellow of the Royal Society 'Dear Professor Callendar, With reference to your letter of January 25, I find that the Manuscript of your paper of the Vapour-Pressure and Osmotic Pressure of a Volatile Solute, communicated on June 17th, 1908, of which a short note only was printed in the Proceedings [of the Royal Society], is still in the hands of the Society. I therefore return it to you herewith, and shall be much obliged if, when acknowledging its safe receipt, you will give me a written assurance, required under the Standing Orders in the case of withdrawn papers, that it is to be regarded as not having been communicated to the Society at all.' 26 January 1909