Terrestrial Globe
Gerard Mercator (1512-1594) is best known for the first use, in 1569, of the map projection bearing his name. This was the first projection on which any given compass bearing could be plotted as a straight line, thereby greatly aiding navigation at sea. Mercator was a prolific publisher of maps and atlases, but he is only known to have produced one version of a globe pair: a terrestrial globe in 1541 and a matching celestial globe in 1551. These globes were produced while Mercator was in Louvain where he had lived since entering the University of Louvain in 1530. Surviving examples of the Mercator globes are rare, and the pair at the Harvard Map Collection are the only known matched pair in America.

A number of interesting features of the Mercator globe can be seen while exploring the images of the globe:

  • The globe is dedicated to Nicolaus Perrenot de Granvella, the prime minister to Emperor Charles V. See the image at 180° 53°S, or the separate image of the dedication cartouche.

  • The better-known parts of the world (particularly Europe) are densely covered with placenames. To fit additional placenames into this area, Mercator resorted to using numbers for some cities, matched with a key that is displayed in the South Atlantic Ocean. Contrast this with what was known about America, which is mostly filled with empty space, other than the eastern coastline.

  • In addition to terrestrial information, the corresponding positions of stars in the celestial sphere are displayed on the map. See, for example, in the image of the North Pole, the location of the stars of the Little Dipper (Ursa Minor), including the North Star (Stella Polaris).

  • Mercator's early interest in the problems of navigation and compass bearing are shown on his globe. See, for example, the curved lines in the image at 36°E 53°S. Each of these curved lines (called loxodromes or rhumb lines) plots a course of a constant compass bearing, and would be a straight line on a chart using the Mercator projection.

  • America is shown as a landmass separated from Asia by a large strait. In 1541 this was a conjecture, and was not based on actual exploration; other early globes (such as the 1533 globe of Johann Schöner) and maps depict America and Asia as a single, connected landmass.

  • Following the predominant belief at the time, the unknown area around the South Pole is shown as a conjectured continent, thought to be a fifth part ("Quinta") of the earth, balancing the known land masses in the north. Mercator's globe clearly identifies this as an unexplored area, drawn here only by conjecture (see the comments in the South Pole image). A promontory extending out from this southern continent towards the tip of Africa is an area described as a Region of Parrots ("Psitacorum regio"), apparently based on a Portuguese account. Another extension of the southern continent (towards what would now be Australia) is labelled with the placenames "Beach" and the kingdom of "Maletur", with the authority of Marco Polo given as the reference.

  • Commentaries at various points on the map attribute information to earlier sources, including a reference to Marco Polo ("M Pauli Veneti") and one to Polo, Kubla Khan ("Cublai"), Pomponius Mela, and Orosius.

  • Depictions of animals of various kinds populate the oceans. Names next to them are interesting links to our own classification of the animal world. One can find images of a "hippopotamus" and a "manati". In South America is shown an animal described as having a pouch to hide and nurse its young. This must be an example of an opposum, the only American marsupial. (Australia, home of the other marsupials, had not yet been discovered.)

On to the Celestial Globe
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