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. Agrees to William Jevons's request to make use of an earlier letter of John Frederick William Herschel's [see William Jevons's 1866-3-7]. 8 March 1866