"4" and, on reverse, "SINGAPORE/P.O." arrival c.d.s. in red; the entire with heavy central vertical filing fold. Photo" /> cover 1864 (10 Dec.) entire to Singapore, bearing 4a. grey-black clearly tied by "147" duplex, showing red crayon<I> "4"</I> and, on reverse, "SINGAPORE/P.O." arrival c.d.s. in red; the entire with heavy central vertical filing fold. Photo | Christie's