10c Brown Allegory UPU Reply Card
Taxed 1/25 (single rate – letter rate)
For a long time, I thought the New York postal clerk erred in taxing this card at the 25-centime letter rate (which would then be doubled upon receipt). But that’s not the case.
Thanks to the kind assistance of an expert on UPU regulations, I have learned that as of April 1, 1879, the issuance of international reply cards and their acceptance could only be done by UPU members who were signatories to the Special Convention on Reply-Paid Postal Cards. The United States was not. This convention remained in force until after the Congress of Vienna, during what is referred to as the Period of Optional Use.
At the Congress of Lisbon in 1885, however, it was decided that all UPU members—not just the signatories—were to honor reply cards and return them to the country of issue. The Lisbon 1885 rules took effect on April 1, 1886—a little over two months after this card was posted. The period from April 1, 1886, to March 31, 1892, is referred to as the Period of Mandatory Return by
The United States did not honor international reply cards until it was required to beginning April 1, 1886. The Luxembourg Post Office may have allowed the originating double card to go to the United States under the mistaken understanding that all UPU members were advancing the acceptance date, but the United States and a number of other members did not. Thus, the reply card was improperly posted in the United States and was properly marked for postage due, although it is unclear whether the addressee (J.B. Schock, Commissioner of Posts at Luxembourg-Gare!) paid the 50 centimes postage due.
And at the Congress of Vienna in 1891, it was decided that all countries would be required to issue reply cards.
So, yet another postal history mystery has now been solved!