The Sphere of the World with Commentaries

as is evident in the case of a coin cast onto the bottom of clear water, which, on account of a similar dispersion of the rays, appears larger than its true magnitude.

THAT THE EARTH IS ROUND.

That the Earth also is round is evident in this way. Signs and stars do not rise and set equally for all men existing everywhere, but they rise and set earlier for those who are toward the east, and they rise and set sooner or later for some; the cause is the swelling of the Earth, which is well evident by those things that occur on high. For one and the same eclipse of the moon by number, which appears to us in the first hour of the night, appears to those in the east around the third hour of the night. Whence it is certain that it was night for them earlier, and the sun set for them earlier than for us. The cause of this matter is only the swelling of the Earth. That the Earth also has a swelling from the north to the south, and conversely, is evident thus: for those existing toward the north, certain stars are of perpetual appearance—namely, those that are close to the arctic pole. Others, however, are of perpetual occultation, such as those that are close to the antarctic pole. If, therefore, anyone were to proceed from the north toward the south, he could proceed to such an extent that the stars which were previously of perpetual appearance to him would now tend toward setting, and the more he would approach the south, the more they would move toward setting. That same man could, in turn, see stars that had previously been of perpetual occultation to him, and conversely.