Letter from C [Charles] Pritchard, Honorary Secretary, Royal Astronomical Society, London, to Sir John [Frederick William] Herschel 'Dear Sir John Herschel I am desired by the Council of the R. Astl: Society to thank you for the valuable Mss on the form of the Achromatic Object Glass which you have confided to their custody. They regard it as a matter of especial interest. I am dear Sir John Yours faithfully C. Pritchard Hon Sec: R: AS:' 20 December 1864