Copy letter from Robert William Frederick Harrison, to Dr Henry Clifton Sorby, Fellow of the Royal Society 'Dear Dr. Sorby, I have the addresses written against the names in your letter. The three marked with a cross are the only ones likely ^I think^ to be of interest ^for your purpose^. Mr. Trotter's exhibit was a model in relief of curves. I am, Yours faithfully, Robert Harrison Asst. Sec. R. S. [Assistant Secretary, Royal Society]'. 28 January 1901