Copper engraving, mm 365x495, coloured by hand, from “Mundus Subterraneus”. Important map by Athanasius Kircher showing 3 maps on a single sheet, providing information on the various theories of the source of the Nile River. The first map shows the observations between 1578 and 1584 by the Portuguese explorer Duarte Lopes. The second map shows Arab cartographic sources. The last (with south at the top) shows the information derived from História da Ethiópia by the Spanish Jesuit missionary Pedro Paez, between 1618 and 1621, which would not be published in a printed edition until 1905-1917. Paez is credited with the discovery of the source of the Blue Nile River in the mountains of Ethiopia (Lake Tana) and reported that there were two "fountains" there. From “Mundus Subterraneus”, one of the most important works by Kircher, where he writes about a volcanic system that was in the core of the earth, connected to the surface. This system was connected with a hydrosystem causing the movement of water to and from the surface – hence ocean currents, earthquakes, tides, and more.Kircher, a Jesuit scholar, was one of the first compilers of knowledge of the physical features of the world. Kircher's work is revolutionary and among the first serious scientific studies of this phenomenon. General good condition, little portion of left bottom margin added. The map is quite rare on the market. AMPR lists two copies offered in 1985 and 1994.