Dorothy Hosler

Research

Professor Dorothy Hosler’s research examines the extraction, processing, and production and functionality of copper and copper-based alloys objects from the Andean region and Western Mesoamerica and the relation of these two ancient technologies to each other. Initial work compared alloy-properties and design of metal objects from Andean South America with those from West Mexico (Michoacán, Guerrero, Jalisco, Nayarit, Colima). Results demonstrated that Andean fabrication techniques, alloy systems and some design types were introduced to Western Mesoamerica sometime after 700 CE. Indigenous artisans worked in this mineral-rich region, where they demonstrated intense interest in the colors of metal sheet (Cu- Ag and other alloys) and in the acoustical properties of copper, copper-silver, copper-tin and copper-arsenic alloy bells and other sounding instruments.

The cultural concern for the acoustical properties of metal was uniquely Mesoamerican and did not replicate Andean cosmologies. Metallic color, especially golden and silvery colors associated with the supernatural is Pan American in scope and probably originated in Colombia. The techniques smiths used to produce these colors varied by region (Hosler 1994).
 
This work is the first research that investigates these ancient metallurgical technologies; that identifies smelting regimes, materials, fabrication methods, design, and functionality (the requisite physical and mechanical properties to perform the action suggested by the design) and the first that distinguishes technical choices from decisions imposed by the laws of physics.

Other Research Foci

Professor Hosler has explored the idea that metalworking had been introduced from coastal Ecuador to western Mesoamerica by sea-going sailing rafts.  Raft design had been documented by 16^th century Italian and Spanish sailors. Europeans had observed that the Ecuadorian rafts carried metal objects—rings, tweezers and other items northward, along the Pacific coast to trade (Hosler 1988). She and her students built and sailed balsa rafts on the Charles River in Boston. Subsequent work demonstrated the feasibility of such voyages (by modeling raft design and other variables Dewan and Hosler 20xx) from coastal Ecuador to the coastal western Mesoamerican metalworking region.
 
In an ethnotechnological study of northern Andean potters, Prof. Hosler identified technical choices and the social variables that shaped them at Las Animas, a village where potters made copies of ancient Ecuadorian and Peruvian pottery vessels and figurines. The potters lived on one side of the town arroyo, the comerciantes or middlemen on the other. The latter sold these “ancient artifacts” at tourist destinations. High-fired hand built pottery copies were fashioned by artisans in the upper quadrant on the potters side of the village, low-fired mold made copies in the lower (Hosler 1996). The study is the first to show that production technologies observed the principle of dual and quadripartite division, an entrenched Andean form of social organization. 

Professor Hosler, Prof. Sandra Burkett and Michael Tarkanian (MIT) undertook the study of Mesoamerican rubber production (Science 1999). Maya peoples used large solid rubber balls in their ballgame, a widespread ritual activity that enacted their beliefs concerning the origins of the universe. Ball courts are often major constituents of Maya architectural complexes. The Olmec, who preceded the Maya, invented the rubber-processing technique wherein latex from the Mexican Castilla elastica tree was combined with the liquid from Ipomea alba—a species of morning glory vine. Castilla elastica is characterized by sulfur containing molecules that facilitate crosslinking, producing an elastic “bouncy” material that these people shaped into large heavy balls. Rubber production by Mesoamerican people predated Goodyear’s “discovery” by some 3,500 years. 
                               
Professor Hosler’s excavation of the copper smelting site of El Manchon (Zaldua and Hosler 2020) followed her extensive survey of the Balsas drainage in the West Mexican states of Guerrero and Michoacán to identify copper smelting sites. She surveyed and mapped La Barranca de Las Fundiciones del Manchón the largest smelting site identified. La Barranca de Las Fundiciones is located in the Sierra Madre del Sur de Guerrero at 1,500 meters. One sector contains voluminous amounts of copper slag and fragments of copper ore. Two others consist of long, solid rectangular house foundations (3-10 meters) replete with potsherds. The potsherds and habitation remains reflect an unknown ethnic or political group although the pottery forms are consistent with other Mesoamerican and West Mexican designs. Carbon-14 dates from charcoal associated with the pottery and the slag range from 1150 CE to 1750 CE. Despite these dates, there was no evidence of Spanish presence at the site—even though the region was invaded around 1521 CE or slightly later. The confusion concerning dates was resolved through research on 16th-century Spanish archival documents and re-examination of one of the El Manchon smelting furnaces. Spanish invaders needed bronze artillery but lacked individuals with the technical know-how to smelt copper. They negotiated with indigenous specialists at El Manchón and other copper smelting sites and granted them freedom from taxation and other obligations in exchange for copper ingots, which indigenous specialists smelted in a unique hybrid (Indigenous-Spanish) bellows-driven furnace capable of producing large volumes of copper metal. For several centuries following the Spanish invasion, the inhabitants of El Manchón were able to continue living at the settlement, as before, producing copper metal for Spanish consumption. Archaeological data also suggest that before the Spanish invasion the inhabitants of El Manchón were smelting copper using blowpipes and small crucibles. The likelihood is strong that they produced copper ingots, which they traded before the Spanish invasion and within Mesoamerica for items such as obsidian and other exotic goods.