Copy letter from Herbert Rix, to Sir Douglas Galton, Fellow of the Royal Society 'Dear Sir Douglas, Our regulations do not admit of any qualifications being added to a certificate after it has once been signed. A "supplementary certificate" can, however, be taken out, and I inclose the necessary form herewith, which must be signed by six Fellows in accordance with the instructions which you will find upon the back thereof. Prof. Corfield's old certificate was duly resuspended. I am, yours truly, H Rix Asst. Sec. R.S. [Assistant Secretary, Royal Society]'. 12 December 1893