The Rubber Balls of the Aztecs 1 (Martijn Hover)

"I don't get it," wrote a member of the Spanish court in the 16h century after a visit to the recently conquered areas in Central America. "When they hit the ground, they bounce back in the air with great speed."
The astonished Spaniard was talking about the rubber balls used by the Aztecs and other Central American nations during a game they played. In this mixture of soccer, volleyball and basketball, two teams of six players attempted to hit the ball through one of the stone rings attached to the wall. In trying to do so, every part of the body could be used except for the hands and feet.
The game, named Chaah, has been around for at least 3,400 years and originally had a ritualistic and religious purpose for the pre-Columbian people of Central America. Remarkably, it developed through the centuries in an increasingly more professional direction, much like the classical Olympic Games and modern-day sports. Every city of significance had a stadium, often with room for thousands of spectators. Rival cities battled out their feuds on the Chaah field and the well-to-do placed large wagers on the outcome of the games. The Aztec capital Tenochtitlán required 16,000 rubber balls from a single province as a tribute.

However, the native Americans used rubber for other purposes besides the production of sports equipment. It was utilised as incense and lip balm, and also for the production of religious figurines. American scientists have researched how the ancient inhabitants of Central America succeeded in manufacturing an elastic material from latex - the sap of the rubber tree. Western chemists did not master this trick until the nineteenth century.
The method applied by the native Americans is "a fantastic example of technology in an unbelievably early stage," according to polymer chemist Frank Bates of the University of Minnesota (USA). Furthermore, this technology is still being used, as a team from the Massachusetts Institute of Technology (MIT) in the United States discovered when travelling through Mexico looking for the basic materials used in the manufacture of rubber as identified in old texts. The team observed how local farmers made cuts in the bark of the rubber tree, Castilla eleastica, collected the latex resin and mixed it with the sap of a climbing plant which wraps itself around the trunk of the tree. The farmers did it exactly as Spanish priests described 400 years ago.
The Americans researched latex and rubber in their laboratories later on, but could not reach any unequivocal conclusions. Rubber is made up of long carbon chains (polymers) which are all linked to one another. Upon closer inspection, latex appeared to be made up of "organic components" which, according to researchers, "probably" prevents the polymers from attaching to one another. Dried latex is brittle and fragile, whereas rubber is pliable and elastic.
The weekly magazine Science reported that researchers are now planning to experiment with various concentrations of the sap of the climbing plant used in rubber production. They want to see if the ancient Maya and Aztecs had the technology to make rubber with all kinds of different characteristics.

¹ Translation from Brabants Dagblad, 30 June 1999

 

[From Natuurrubber 17, 1st quarter 2000]