Dorothy Hosler still remembers the hot spring afternoon in 1998 when she hiked into the remote mountains of Guerrero, Mexico, and found what she had been seeking for four months: the first known pre-Columbian metalworking site north of Ecuador, inhabited sometime after 1100 c.e. Hosler, a professor of archaeology and ancient technology at MIT, and two villagers had been traveling for hours by jeep, horseback, and foot to reach the site, which was nestled in a forest high in the mountains. She had already scouted dozens of archaeological sites, but to no avail. Her guides assured her that their destination, El Manchon, was special, but she wasnt entirely persuaded. I had been on many dead-end trips with people who said, Theres something you absolutely have to see, and wed get way out in the middle of nowhere and there wouldnt be anything. So I had no expectations, Hosler says.
When they finally arrived, Hoslers doubts faded. She found a wooded site littered with pottery shards and obsidian, a shiny, black volcanic glass used for making tools. She saw 36 mounds in two areas, the longest stretching up to 22 meters and about two or three meters high, that were obviously human made. Hoslers guides led her across a stream to a large clearing. Seven or eight circular stone ruins, each about a meter and a half in diameter, lay scattered under the open sky. Hosler guessed that they were furnaces used to draw copper out of ore. Slag, a brittle by-product of smelting, covered the ground and snapped underfoot as she surveyed the site. I thought, I cant believe what Im seeing. I must be imagining this, she recalls. Hosler knew she had hit the jackpot. The slag was a clear indication that smelting had taken place, and the pottery shards and ruins of buildings led her to believe that the site was indeed pre-Columbian. It took years of delicate negotiations with government officials, but she finally obtained permission in 2001 to excavate the site and has been going back every summer since. Hosler hopes her ongoing excavation will answer technical questions about the smelting process and also help explain the cultural and religious role of metalworking in ancient Mexican societies.
Hoslers search for El Manchon brought much of the pain and pleasure archaeologists typically encounter while hunting down the ideal site. But her experience was made atypical by her expertise in metallurgywhich few archaeologists possessand access to a laboratory devoted to the analysis of archaeological materials. In fact, just after Hosler returned from Mexico, the Department of Materials Science and Engineering began to offer a doctoral program in archaeological materialsthe only program of its kind in the world. At the same time, it created an experimental undergraduate program in archaeology and materials, which became an official major in fall 2004. The aim of the program is to teach archaeology from the perspective of engineering. Although its increasingly common for archaeologists to have backgrounds in chemistry, biology, or geology, Hosler says, few are trained in engineering. But if they were, they would have the tools to answer not only the what, where, when, and who about a particular site or artifact but also the how and why of an artifacts creation. Applying an engineers perspective opens up an enormous field of inquiry, says Hosler. There are so many problems that havent even been approached. Hosler and her students have already broken new ground by examining the technical choices ancient people made when, for example, constructing a raft or making a rubber ball. Such choices help define cultures, Hosler says, which are exactly what archaeologists struggle to understand.