Leaving out gifts of metal tools in gardens or tied to ropes in a forest clearing, they wooed isolated groups into contact, and later forced them to work for consumer goods they had come to depend on. (sciencemag.org)
We have used these fuels to drive our technological innovations of all kinds, from the production of metal tools in coal - burning furnaces centuries ago to the development of plastic bags, a modern scourge. (hubpages.com)