1870, Presidents 2 c. brown and 12 c. violet, tied by corn cancel to an envelope to Norway, transit cds. "CHRISTIANA 19 7 1871", the 15 cents rate (July 1870, closed mail via the North German Union) was underpaid by one cent, hence taxed with red "2" struck on front; fine and rare transatlantic mail as prepayment was then optional
