That portion of Europe, Asia, and Africa known to the ancients, whether regarded as an island, or as separated from the rest of the world by climatic conditions merely, or by ignorance, formed a distinct concept and was known by a particular name, ἡ οἰκουμένη. Originally supposed to be circular, it was later thought to be oblong and as having a length more than double its width. Those who believed in its insularity likened its shape to a sling, or to an outspread chlamys or military cloak, and assumed that it lay wholly within the northern hemisphere. In absolute figures, the length of the known world was placed by Eratosthenes at 77,800 stadia, and by Strabo at 70,000. The latter figure remained the common estimate until Marinus of Tyre, in the second century a.d., receiving direct information from the silk-traders of a caravan route to China, substituted the portentous exaggeration of 90,000 stadia on the parallel of Rhodes, or 225°. Ptolemy, who followed Marinus in many things, shrank from the naïveté whereby the Tyrian had interpreted a seven months’ caravan journey to represent seven months’ travelling in a direct line at the rate of twenty miles a day, and cut down his figures to 180°, or 72,000 stadia.[282] It appears, therefore, that Strabo considered the known world as occupying not much over one third of the circuit of the temperate zone, while Marinus, who adopted 180,000 stadia as the measure of the earth, claimed a knowledge of two thirds of that zone, and supposed that land extended indefinitely eastward beyond the limit of knowledge.
What did the ancients picture to themselves of this unknown portion of the globe? The more imaginative found there a home for ancient myth and modern fable; the geographers, severely practical, excluded it from the scope of their survey; philosophers and physicists could easily supply from theory what they did not know as fact. Pythagoras, it is said, had taught that the whole surface of the earth was inhabited. Aristotle demonstrated that the southern hemisphere must have its temperate zone, where winds similar to our own prevailed; his successors elaborated the hint into a systematized nomenclature, whereby the inhabitants of the earth were divided into four classes, according to their location upon the surface of the earth with relation to one another.[283]
This system was furthest developed by the oceanic school. The rival of Eratosthenes, Crates of Mallus (who achieved fame by the construction of a large globe), assumed the existence of a southern continent, separated from the known world by the equatorial ocean; it is possible that he introduced the idea of providing a distinct residence for each class of earth-dwellers, by postulating four island continents, one in each quarter of the globe. Eratosthenes probably thought that there were inhabitable regions in the southern hemisphere, and Strabo added that there might be two, or even more, habitable earths in the northern temperate zone, especially near the parallel of Rhodes.[284] Crates introduced his views at Rome, and the oceanic theory remained a favorite with the Roman physicists. It was avowed by Pliny, who championed the existence of antipodes against the vulgar disbelief. In the fine episode in the last book of Cicero’s Republic, the younger Scipio relates a dream, wherein the elder hero of his name, Scipio Africanus, conveying him to the lofty heights of the Milky Way, emphasized the futility of fame by showing him upon the earth the regions to which his name could never penetrate: “Thou seest in what few places the earth is inhabited, and those how scant; great deserts lie between them, and they who dwell upon the earth are not only so scattered that naught can spread from one community to another, but so that some live off in an oblique direction from you, some off toward the side, and some even dwell directly opposite to you.”[285] Mela confines himself to a mention of the Antichthones, who live in the temperate zone in the south, and are cut off from us by the intervening torrid zone.[286]
MACROBIUS
From Macrobii Ambrosii Aurelii Theodosii in Somnium Scipionis, Lib. II. (Lugduni, 1560).
Indeed, the southern continent, the other world, as it was called,[287] made a more distinct impression than the possible other continents in the northern hemisphere. Hipparchus thought that Trapobene might be a part of this southern world, and the idea that the Nile had its source there was widespread: some supposing that it flowed beneath the equatorial ocean; others believing, with Ptolemy, that Africa was connected with the southern continent. The latter doctrine was shattered by the discovery of the Cape of Good Hope; but the continent was revived when Tierra del Fuego, Australia, and New Zealand were discovered, and attained gigantic size on the maps of the sixteenth and seventeenth centuries only within the last two centuries has it shrunk to the present limits of the antarctic ice.