black datestamp on folded letter to London, England, two pairs of 1851 12c Black (17, positions 33-34L1 and 87-88L1) tied by magenta grids for a total 48c postage, red "38" credit to United Kingdom, carried via Cunard's Persia departing New York September 17 and arriving Liverpool September 27, London "Paid" September 29 datestamp, very fine double rate letter