Copy letter, from Sir John Herschel to John Wrottesley, dated at Collingwood Copy of letter, copied by Isabella Herschel in 1875 as part of the correspondence project led by Colonel John Herschel FRS following the death of his father. Thanks John Wrottesley for his double star catalogue; John Frederick William Herschel comments on a few items contained therein. 2 November 1860