1867 (Oct. 8) Amriswil, Switzerland to Aurora, Ill., unpaid cover with "Amriswil 8 Oct 67" origin cds, red Paris (10.8) transit with black "18" cent debit to U.S., carried by Allan Line Austrian from Londonderry Oct. 11 to Quebec arriving Oct. 21, "Chicago Am. Pkt. '21' Oct 24" exchange debit cds and matching "27/U.S. Notes" depreciated currency marking, additional boxed "Am. Service" h.s. applied, F.-V.F. Estimate  $300 - 400. London sent Chicago mails on Allan Line steamers from Londonderry to Quebec. Letter carried by train from Quebec to Chicago where the boxed "Am. Service" marking was struck and marked for 21¢ postage due in coin or 27¢ in depreciated currency. Because French mails sent on Allan Line steamers were considered to be carried on British packets for accounting purposes, U.S. entitled to only 3¢ of 21¢ rate. $0 (Image)