细节
cover 1871 envelope to Constantinople bearing Duloz type 20pa. green and 2pi. red, both cancelled by superb Turkish double oval framed seal of Podgorica, reverse with red wax seal and (7.4) arrival c.d.s.; the envelope with a couple of imperfections at left, all of which are clear of adhesives. Extremely rare, stated to be the only recorded example of this cancellation on cover. Photo in colour