Copy letter, from Sir John Herschel to Stephen Peter Rigaud, dated at Leamington, Warwick Copy of letter, copied as part of the correspondence project led by Colonel John Herschel FRS following the death of his father. Thanks Stephen Rigaud for letter announcing Stephen Rigaud's discovery of observation of comet of 1759 [see Stephen Rigaud's 1829-3-18]. Asks Stephen Rigaud to communicate information directly to [F. W.] Bessel. Will keep Stephen Rigaud's letter confidential. 25 March 1829