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] [Illustration: 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. [Illustration: MACROBIUS From _Avr. Theodosii Macrobii Opera_ (Lipsiæ, 1774).]