Copy letter, from Sir John Herschel to William Stanley Jevons, dated at Collingwood Copy of letter, copied as part of the correspondence project led by Colonel John Herschel FRS following the death of his father. Thanks William Jevons for his papers on clouds [see William Jevons's 1861-7-21]. John Frederick William Herschel had not seen these, but praises their contents. 30 July 1861