Copy letter, from Sir John Herschel to Robert Harley, 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. Expresses thanks for Robert Harley, in a paper on George Boole in the British Quarterly Review, giving John Frederick William Herschel credit for having published 'my introduction of the mode of separation of the symbol of differentiation from the differentiated function and executing on it operations analogous to those of common algebra.' 19 July 1866