_:vb6829624	<http://www.w3.org/1999/02/22-rdf-syntax-ns#value>	"Energy has seldom been found where we need it when we want it. Ancient nomads, wishing to ward off the evening chill and enjoy a meal around a campfire, had to collect wood and then spend time and effort coaxing the heat of friction out from between sticks to kindle a flame."@en .
_:vb6829624	<http://purl.org/dc/terms/bibliographicCitation>	"2013 July-August, Henry Petroski, \u201CGeothermal Energy\u201D, in American Scientist, volume 101, number 4:"@en .