cover 1872 envelope with 1871 1pi. yellow tied by unclear seal cancel (probably Istanbul) with Ismit seal struck beneath, reverse bearing 1868 1pi. postage due adhesive, tied by oval bi-lingual "BAGHTCHE CAPUSSI" d.s. and with Stamboul c.d.s. adjacent; a good example of a postage due on a piece of mail passing through the City Post system