Copy of draft letter, from Sir John Herschel to Francis Lunn Copy of draft letter, copied as part of the correspondence project led by Colonel John Herschel FRS following the death of his father. Hears that the editors of Encyclopaedia Metropolitana have taken exception to John Frederick William Herschel's plan to write a work on Light for the Cabinet Cyclopaedia. Gives his views why the works should not conflict. 1829?