1857 (May 20) Boston, Mass. to Jerez de la Frontera, Spain, folded letter with red "Boston Paid 20 May Br. Pkt." exchange cds with manuscript "37" prepaid rating for British mail rate via France prepaid to Spanish border only, red crayon "32" cent U.S. credit to G.B., carried by Cunard Line Europa from Boston May 20 to Liverpool arriving May 31, red London (6.1) with circled "PP" h.s., Calais (6.1) transit, Cadiz (6.10) arrival backstamp and black "4R" reales postage due rating, Very Fine. Estimate  $200 - 300. $0 (Image)