It was thought that Africa did not extend to the equator, or at least was not habitable to the equator. Below the equator there was thought to be water but beyond the uninhabitable and impassable torrid zone, a habitable region existed. The map of Lambertus (Slide #217) well represents this early theory. Pomponius Mela (Slide #116) called the inhabitants of this southern region Antichthoni, their country being unknown to us because of the torrid zone intervening. Pliny, and after him Solinus, says that for a long time the island of Taprobana [Ceylon/Sri Lanka] was thought to be the region occupied by the Antichthoni.
That Strabo (Slide #115), at a later date, had this Pergamenian example in mind when stating certain rules to be observed in the construction of globes seems probable, since he makes mention of Crates' globe. Strabo alone among ancient writers, so far as we at presently know, treats terrestrial globes practically. He thought that a globe to be serviceable should be of large size, and his reasoning can readily be understood, for what at that time was really known of the earth's surface was small indeed in comparison with what was unknown. Should one not make use of a sphere of large dimensions, the habitable regions in comparison with the earth's entire surface, would occupy but small space. What Strabo states in his geography is interesting and may here well be cited.
Whoever would represent the real earth as near as possible by artificial means, should make a sphere like that of Crates, and upon this draw the quadrilateral within which his chart of geography is to be placed. For this purpose however a large globe is necessary since the section mentioned, though but a very small portion of the entire sphere, must be capable of containing properly all the regions of the habitable earth and of presenting an accurate view of them to those who wish to consult it. Anyone who is able will certainly do well to obtain such a globe. But it should have a diameter of not less than ten feet; those who cannot obtain a globe of this size, or one nearly as large, had better draw their charts on a plane surface of not less than seven feet. Draw straight lines for the parallels, and others at right angles to these. We can easily imagine how the eye can transfer the figure and extent (of these lines) from a plane surface to one that is spherical. The meridians of each country on the globe have a tendency to unite in a single point at the poles; nevertheless on the surface of a plane map there would be no advantage if the right lines alone which should represent the meridians were drawn slightly to converge.
Crates' motive for his cartography was partly literary, interpreting Ulysses' wanderings, and historical rather than purely scientific. As a Stoic, he proclaimed Homer the founder of geography, crediting him with belief in a spherical earth and commenting on his poems accordingly. To explain Homer's line, "The Ethiopians who dwell sundered in twain, the farthermost of men", Crates argued that on each side of an equatorial ocean there lived the Ethiopians, divided by the ocean, one group in the Northern Hemisphere, the other group in the Southern, without any interchange between them. Again Strabo reports:
Crates, following the mere form of mathematical demonstration, says that the torrid zone is "occupied" by Oceanus, and that on both sides of this zone are the temperate zones, the one being on our side, while the other is on the opposite side of it. Now, just as these Ethiopians on our side of Oceanus, who face the south throughout the whole length of the inhabited world, are called the most remote of the one group of peoples, since they dwell on the shores of Oceanus, so too, Crates thinks, we must conceive that on the other side of Oceanus also there are Ethiopians, the most remote of the other group of peoples in the temperate zone, since they dwell on the shores of this same Oceanus.
The scientific thinking behind the geography of Crates' globe was derived directly from the teaching of Eratosthenes about the relative size of the known world. By combining the geometric approach of his predecessor with his own interpretation of Homer (Slide #105), he represented four inhabited worlds on the surface of his terrestrial globe. Two were in the Northern Hemisphere, the one where the Greeks lived, occupying far less than half of the Northern Hemisphere, and another symmetrically situated in the other half. Two other inhabited worlds are found in the Southern Hemisphere, symmetrical with the two north of the equator. These four worlds were separated by oceans along the equator (occupying the torrid zone made uninhabitable by heat) and along a meridian. The inhabited areas were thus islands, with no communication between them.
It is clear that this conception of four symmetrical land areas was a direct consequence of the geometry of the sphere and the size Eratosthenes attributed to the inhabited world in relation to the total globe. Crates demonstrated this by drawing the four areas on the surface of his globe and suggesting that the three unknown lands could be similar to the known one. To give it further credibility, he also drew in the main parallel circles, emphasizing those defining the zones: these were the tropics (at 24° distance from the equator), between which flowed the Ocean as envisaged by Homer, and the two polar circles (at 66° distance from the equator).
Crates' globe was thus a product of theoretical mathematical cartography, communicating an image of the world that was very far from reality. Our understanding of the globe's physical characteristics is meager, and there is no evidence to suggest how or of what material it was made, but its influence on the history of cartographic thought has been considerable. The concept of the equatorial ocean was transmitted to medieval Europe through Macrobius' commentary on Cicero's Dream of Scipio. Scholars of later times also vied eagerly to give adequate names to these unknown worlds, but on the whole they did not doubt their existence.
LOCATION: (this globe only exists as a reconstruction)
Bagrow, L., History of Cartography, p. 33.
*Bunbury, E., History of Ancient Geography, Chapter V.
*Dilke, O.A.W., Greek and Roman Maps, p. 36.
Landström, B., Bold Voyages and Great Explorers, p. 43.
*Raisz, E., General Cartography, p. 10.
*Stevenson, E., Terrestrial Globes, p. 7.