Copy letter from Robert William Frederick Harrison, to Sir William Abney, Fellow of the Royal Society 'Dear Sir William Abney, In accordance with the request contained in your letter of the 11th inst. [instant] to Professor Larmor I am to-day returning Mr Dennis Taylor's paper "A Practical Method of Computing the Oblique Foci of Optical Systems" to the Author at Messrs Cooke and Sons Optical Works, York. I am, faithfully yours, Robt [Robert] Harrison Asst. Sec. R.S. [Assistant Secretary, Royal Society]'. 14 March 1904