Air Mail cover 1935 (7 July) envelope registered to Brazil bearing Air 15m. on 10m. (showing dramatic upward shift of surcharge) and 10pi. on 4½pi., tied by single oval "REGISTERED/KHARTOUM" d.s. and showing red South American Flight handstamp adjacent, annotated in red ink at top "..By airship Graf Zeppelin to Brazil via Friedrichshafen" and with "BY AIRSHIP/GRAF ZEPPELIN" label alongside, reverse with Pernambuco (18.6) arrival. Photo