Copy letter, from Sir John Herschel to John Stuart Mill, 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. Proceeds to show John Stuart Mill in detail that Comte's nebular hypothesis is arguing in a 'vicious circle' [see John Frederick William Herschel's 1845-7-10]. 16 July 1845