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. Comments on John Frederick William Herschel's disagreement with the nebular hypothesis of Auguste Comte, and points out to John Stuart Mill that John Frederick William Herschel disagrees with some of John Stuart Mill's writings on physical science as well. 10 July 1845