Copy of draft letter, from Sir John Herschel to Alfred Smee Copy of draft letter, copied as part of the correspondence project led by Colonel John Herschel FRS following the death of his father. On the basis of some compounds referred to by Alfred Smee [see 1842-5-10], John Frederick William Herschel has now developed a new form of photography using gold as a stimulant; John Frederick William Herschel calls it the 'Argyrotype'. 15 June 1842