Copy letter, from Sir John Herschel to William Henry Smyth, 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. Sends positions of Biela's Comet. Has much success with repolished telescope mirrors and collimator. Designs equatorial revolving roof for Cape observations; sends sketches. Compares William Henry Smyth's, W. R. Dawes's, and John Frederick William Herschel's observations of Gamma Virginis. 25 September 1832