A very good used Registered cover from Medellin. Colombia (12/7/1930) to Danzig (16/8/1930) via New York (4/8/1930). Danzig is now the Polish port of Gdansk. Advertising envelope is for Carlos Arturo Jaramillio. a stamp dealer based in Medellin. The cover is incorrectly franked with 12c on the reverse. instead of 8c foreign postage. 8c registration fee applied.