British Guiana. (French Guyane). 1852. Stamp-less envelope written from Cayenne cancelled by oval 'Poste Aux Lettres/de Cayenne Francaise' (Jamet 3), endorsed 'par la voie Anglaise' and routed via British Guyana with British Post Office Demerara date stamp on reverse 'Ja 10 1852' with framed accountancy 'Colonies/ & art. 13.' in red and London transit, French entry cachet '10th Feb' and charged with hand-struck '30' for double letter rate and Bordeaux receiver. Very fine and scarce combination.