The general international conventions relating to the Universal Postal Union have always recognized the right of adherent countries to make supplemental agreements and to form limited postal unions. The first convention among American countries was signed on February 2, 1911, and was restricted to the countries of South America.1 By this convention the South American Postal Bureau was established at Montevideo.
An important provision of the South American Convention of 1911 was that for free transportation of international mail across a country on the route between the country of origin and the country of destination. This principle had long been in dispute at the congresses of the Universal Postal Union, but had always been voted down. It arose again in 1920 at the Madrid Congress of the Universal Postal Union, and in connection with other questions resulted ultimately in a supplementary postal union embracing Spain and the American states.
In most of the questions which arose at the Madrid congress, Spain voted with the delegates from the western hemisphere, and when a convention between the American countries was signed at Madrid on November 10, 1920 ( 41 Stat. L. 2141), Spain was the only European power which was a signatory.
The convention of 1920 did not affect the South American Postal Bureau established by the convention____________________