Copy of letter, from Sir John Herschel to William Henry Fitton, dated at Slough Copy of letter, copied as part of the correspondence project led by Colonel John Herschel FRS following the death of his father. Accepts invitation to William Henry Fitton's party on 19th, but will miss reading of Adam Sedgwick's and R. I. Murchison's paper. Chemical composition of 'Fish limestone.' 14 May 1828