Copy letter from Robert William Frederick Harrison to Professor H [Hugh] L [Longbourne] Callendar, Fellow of the Royal Society 'Dear Professor Callendar, Many thanks for your note about Smith's certificate. I think your written explanation, which I will attach to the certificate, will be quite sufficient and you need not fear the certificate being considered invalid. The worst that could happen, I think, as I said in my former letter, would be that the pasted on name might not be printed in the printed copy of the certificate, but I expect there will be no objection raised.' 1 January 1909