Postage stamps and postal history of Mexico The regency had previously changed the official currency under which one peso equaled 8 reales to a decimal system in which one peso equaled 100 centavos. In making the conversion postal rates were rounded up, for example, the rate of one real being equal to 12.5 centavos was rounded up to 13 centavos. The stamps, as a result, were issued in values of 7c, 13c, 25c, and 50c. These stamps were issued with the year and invoice number and with or without the district name, but some issued in exchange for Eagle stamps were issued only with the Mexico City
Gold standard to Congress the value of a decimal system. This system would also apply to monies in the United States. The question was what type of standard: gold, silver or both. The United States adopted a silver standard based on the Spanish milled dollar in 1785. From 1860 to 1871 various attempts to resurrect bi-metallic standards were made, including one based on the gold and silver franc; however, with the rapid influx of silver from new deposits, the expectation of scarce silver ended. The interaction between central banking and currency basis formed the primary source of monetary instability during this period.