Copy letter, from Sir John Herschel to Charles Babbage, dated at Slough Copy of letter, copied as part of the correspondence project led by Colonel John Herschel FRS following the death of his father. It looks as though their projected Cornish excursion will have to be postponed for a time. Gives the formula for the conversion of rags into sugar. A Finnish astronomer wishes to be elected a member of the Astronomical Society. Observations on the theory of parallax. 12 August 1820