American Postal Machine Company, Boston, Mass, Oct 22, 1914. Slogan flag cancel "Pure Food Exposition" on cover tying 1¢ Pan-Pacific, Very Fine, The A.P.M.C. apparently had a booth at this local Boston exhibition and used this flag die to create 'souvenir' hand back covers, which did not actually pass through the mail. Estimate  $200 - 300. $0 (Image)