Copy letter from Herbert Rix, to John Walton Capstick, Trinity College, Cambridge 'Dear Sir, Inclosed herewith you will find photo. (Fig [figure] 2 in your recent paper). The engraver asks for a description, as the photo is rather vague and not intelligible to him. He is an intelligent man, and will do it better if he understand what it is and which parts are essential.The other figures are in hand. Yours truly, H Rix Asst. Sec. R.S. [Assistant Secretary, Royal Society]'. 3 November 1893