On an island in a small river in Norway's Nord-Trøndelag County, archaeologists have discovered a 14th-century copper smeltery. “This is the first evidence that copper was produced from copper ore in Norway during the Middle Ages,” says Associate Professor Lars F. Stenvik, at the Museum of Natural History and Archaeology in Trondheim.
The facility was "surprisingly sophisticated." According to Stenvik, "one eye-popper was a split log that could have been used as a shaft in a drive gear that would enable its makers to capture the power of the rushing river. The shaft was inlaid with some sort of hinge that could have been attached to a pair of bellows."