Copy letter, from Sir John Herschel to William Whewell, 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 Whewell for and comments on William Whewell's Lectures on Political Economy. Has learned that the theory of rent is exploded. John Frederick William Herschel's daughter Julia is seriously ill. 22 January 1863