Diodorus tells us that the Chaldeans considered the earth hollow and boat-shaped—perhaps turned upside down—and this doctrine was introduced into Greece by Heraclitus of Ephesus.
Fig. 29.—The Earth of Anaximander.
Anaximander represents the earth as a cylinder, the upper face of which alone is inhabited. This cylinder, he states, is one-third as high as its diameter, and it floats freely in the centre of the celestial vault, because there is no reason why it should move to one side rather than the other. Leucippus, Democritus, Heraclitus, and Anaxagoras all adopted this purely imaginary form. Europe made the northern half, and Lybia (Africa) and Asia the southern, while Delphi was in the centre.
Anaximenes, without giving a precise opinion as to the form of the earth, made it out to be supported on compressed air, though he gave no idea as to how the air was to be compressed.
Plato thought to improve upon these ideas by making the earth cubical. The cube, which is bound by six equal faces, appeared to him the most perfect of solids, and therefore most suitable for the earth, which was to stand in the centre of the universe.
Fig. 30.—Plato's Cubical Earth.
Eudoxus, who in his long voyages throughout Greece and Egypt had seen new constellations appear as he went south, while others to the north disappeared, deduced the sphericity of the earth, in which opinion he was followed by Archimedes, and, as we have seen, by Aristotle.
According to Achilles Tatius, Xenophanes gave to the earth the shape of an immense inclined plane, which stretched out to infinity. He drew it in the form of a vast mountain. The summit only was inhabited by men, and round it circulated the stars, and the base was at an infinite depth. Hesiod had before this obscurely said: "The abyss is surrounded by a brazen barrier; above it rest the roots of the earth." Epicurus and his school were well pleased with this representation. If such were the foundations of the earth, then it was impossible that the sun, and moon, and stars should complete their revolutions beneath it. A solid and indefinite support being once admitted, the Epicurean ideas about the stars were a necessary consequence; the stars must inevitably be put out each day in the west, since they are not seen to return to the place whence they started, and they must be rekindled some hours afterwards in the east. In the days of Augustus, Cleomedes still finds himself obliged to combat these Epicurean ideas about the setting and rising of the sun and stars. "These stupid ideas," he says, "have no other foundation than an old woman's story—that the Iberians hear each night the hissing noise made by the burning sun as it is extinguished, like a hot iron in the waters of the ocean." Modern travellers have shown us that similar ideas about the support of the earth have been entertained by more remote people. Thus, in the opinion of the Greenlanders, handed down from antiquity to our own days, the earth is supported on pillars, which are so consumed by time that they often crack, and were it not that they are supported by the incantations of the magicians, they would long since have broken down. This idea of the breaking of the pillars may possibly have originated in the known sinking of the land beneath the sea, which is still going on even at the present day.