Kircher's subterranean Earth. Artwork of the internal fires of the Earth, from the work Mundus Subterraneus (Dutch 1668 edition) by the German Jesuit scholar Athanasius Kircher (circa 1601-1680). The artwork shows volcanoes on the surface of the Earth, and underground fires and water channels causing them to erupt. Kircher's theory was that underground water channels, heated by the internal fires of the Earth, emerged in the sea (causing the tides) and in mountains (causing volcanoes). The caption at top is in Latin. In the corners of the artwork are figures representing the four winds. More Latin text is at bottom.