Athanasius Kircher’s ‘Mundus Subterraneus’ (1664)

Between mid-December 1631 and the end of January 1632 Mount Vesuvius produced its most violent eruption since that of AD79, a VEI=5 event that included central vent and radial fissure eruptions, pyroclastic flows, lahars and volcanic tsunamis. The eruption killed perhaps 4000 people, sweeping away the villages at the foot of the volcano and severely damaging a number of larger towns including Torre del Greco, which was perhaps two-thirds destroyed and where most of the fatalities occurred. This eruption had a major impact on contemporaries throughout Europe, giving rise to an upsurge of interest in the study of volcanoes. Among those drawn to the close scrutiny of Vesuvius was the Jesuit priest and polymath Athanasius Kircher (1609-1680).

Despite having had his youth in his German homeland disrupted by the Thirty Years War, Kircher had shown early promise in the sciences and by the early 1630s he was known for his work in mathematics, mechanics and magnetism. From 1633 he worked in Rome as a scholar and teacher, and in 1637-8 he travelled in the south of Italy investigating earthquakes and volcanic phenomena including Etna, Stromboli and Vesuvius. While visiting Vesuvius he climbed all over the mountain making observations, even having himself lowered by rope into the crater. From 1638 onwards he devoted himself to research and writing at the Jesuit Collegio Romano, one of the intellectual powerhouses of early modern science, producing a vast number of publications on subjects including music, astronomy, linguistics, archaeology, magnetism, mechanics and geology.

Kircher’s interest in geology, and particularly in volcanoes and earthquakes, bore magnificent fruit in his Mundus Subterraneus, published in twelve volumes between 1664 and 1678. Kircher postulated a central source of heat at the centre of the globe, and produced a stunning cross-section of the Earth (included in volume III of his work) showing a central mass of flame feeding heat to the surface through a complex network of channels and fissures and subsidiary bodies of fire distributed through the interior. Volcanoes were created where the Earth’s internal fires escaped at the surface, and also served to draw in air to sustain those subterranean fires. The source of the combustion was the combining of salt, sulphur, bitumen and other inflammable and explosive materials within the Earth. The idea of subterranean fire innate to the Earth developed during the fifteenth and sixteenth centuries as a means of accounting for the presence and distribution of hot springs; its application to the problem of volcanoes was a natural development, significant for reflecting an awareness of volcanoes as a global phenomenon produced by a global process, rather than the purely localized product of wind action upon deposits of combustible materials. Kircher’s very influential work can be seen as playing an important part in the dissemination of this notion.

For all ‘Saturday volcano art’ articles: Saturday volcano art « The Volcanism Blog.