Autograph Letter Signed, to Lady Davy, informing her that her picture does not need varnishing, explaining how he has tested the surface of the picture by washing it “with a half wet spunge”. 4 pp. 7 x 4½ inches, in good condition. With the original envelope. 2 Carlton Gardens, London, 13 September 1850. Penry Williams (1798-1885), artist.