Camerouns. (Brazil). 1916. Brazil postal stationery envelope 100r upgraded with Yvert 131, 100r rose tied by Corumba double ring '10/4' endorsed 'via Sao Paulo' and 'Dakar/Senegal' addressed to Libreville, Gabon with Dakar/Senegal '10/5' and Libreville/Gabon '20/5' arrival then forwarded to the Camerouns with 'Duala/Cameroun' arrival '5/6' on reverse. Very nice item of incoming mail.