Positioning the Earth in the Eighteenth Century: Mapping the Cosmographical and Terraqueous Globes in Two Hemispheres
by Matthew Edney
Modern Western world maps have sustained several world views. In the seventeenth century, European geographers generally mapped the cosmographical globe, i.e., the earth as it is connected by metaphysics and geometry to the rest of the cosmos [map 1]. The double-hemisphere world maps that were then dominant were made on the same stereographic projection as star charts; their spandrels were full of cosmographical imagery and astronomical diagrams; globes were used in celestial and terrestrial pairs to model the apparent movements of the stars and the sun, respectively; the line of the ecliptic (i.e., the sun’s path from solstice to solstice) was transferred from the globes to world maps.
In the eighteenth century, as heliocentrism eroded the privileged status of cosmographical studies within education and as western European nations began to establish new empires in Asia, geographers increasingly mapped what they called the terraqueous globe, i.e., the ball of earth and water, without reference to the rest of the cosmos. In part they modified the existing convention of double-hemisphere world maps [map 2], and they also increasingly adopted Mercator’s projection—then still uncommon—for geopolitical mapping.
By the end of the eighteenth century, the terraqueous globe had become the culturally dominant conception of the world. Nineteenth-century geographers kept the double-hemisphere format and the separation of the old world from the new, but replaced the stereographic with a new, lower distortion “globular” projection; they filled the maps’ spandrels with comparative diagrams of mountain heights and river lengths, and could also add ethnographic and imperialistic imagery [map 3]. The hemispheres themselves showed mountain chains, river systems, and the division of the continents. At the same time, Mercator’s projection was used to map the political divisions of the earth, the new empires, and their maritime interconnections.
Nova et Accuratissima Totius Terrarum Orbis Tabula Auctore Joanne Blaeu
An exemplary map of the cosmographical globe. The two hemispheres are mapped with the equatorial-aspect stereographic projection, as used for star charts, although the map does not feature the line of the ecliptic. Across the lower register are allegories of the four seasons (caused by the earth-sun geometry); across the upper are the planets, represented by the Roman gods, and their orbits around the sun, with a double orbit shown for the earth. This standard division of the hemispheres neatly divided the world into the old and the new worlds.
Nouvelle mappe monde dediée au progrès de nos connoissances
Although unable to break from the convention of using the stereographic projection, this world map is one of several made in the 1700s that used an oblique aspect, so as to divide the world into a land and an ocean hemisphere. These maps truly depicted the terraqueous globe. They all lacked cosmographical iconography—here, the allegory is of Geometria calling on the light of reason—and most of them had nationalistic overtones, in that the land hemisphere was centered on the geographers’ respective capital cities (London, Berlin, Vienna, Paris). Boullanger, however, consciously avoided such nationalism by centering his land hemisphere on the Paris meridian, but at 45°N a couple of degrees south of Paris itself.
World at One View
An exemplary map of the terraqueous globe, showing the earth’s mountains, river chains, and continental divisions. In addition to the serried ranks of high mountains and long rivers, both emphasizing the global environment, this map bears a series of ethnographic imagery informed by Western imperialism and a bottom register that shows the “westward course of empire,” the belief that underpinned the U.S. faith in manifest destiny.