Air Mail cover 1912 (Feb.) Bork-Brück Flight, (-) violet AN IMPERFORATE EXAMPLE ON GLAZED PAPER, AFFIXED TO 1912 (26 FEB.) COVER TO HAMBURG, cancelled by "BRÜCK" c.d.s. and showing circular "Flugpost Bork und Umgegend durch Gradeflieger" cachet in violet, reverse with decorative "BORK/FLUG-WALD-/FELD KOLONIE" blue seal. AN OUTSTANDING AIRMAIL RARITY FROM THE PIONEER PERIOD. M. 1B, DM.40,000. Photo and on back cover