U5 1879 (15 Oct.) U.P.U. red on white stationery card to U.S.A., bearing 3c. on 16c. yellow tied by legible "S2" obliterator in black, showing fine Swatow c.d.s. with, on reverse, Hong Kong transit d.s.; the card with some heavy damp staining and the address rather faint. A very rare item. Photo