Copy letter, from Sir John Herschel to William Henry Smyth, dated at Collingwood Copy of a letter. Sends paper by F. W. A. Argelander, which G. B. Airy wishes to have published. Revising chapter on perturbations in his Treatise Astr. Will include theory of motions of the apsides and the variations of the eccentricities. 20 September 1848