1931, Wilkins-Ellsworth Trans-Arctic Submarine Expedition. Neat cover with purple Expedition cachet, franked with 1½d G.B. KGV definitive postmarked "London 5 Oct 31" and U.S.A. 2¢ & 5¢ definitives, usual smudge cancels with New York May 8 1931 duplex; couple stains do not detract; this dual franking was typical for mail associated with the Expedition, still Very Fine. Estimate  $100 - 150. $0 (Image)