ITS EAELIEST STAGES. 133 



value of his opinion; it may have been no better founded than a 

 different opinion ascribed to him by Laertius, that the earth had the 

 shape of a pillar. Probably, the authors of the doctrine of the globular 

 form of the earth were led to it, as we have said, by observing the 

 different height of the pole at different places. They would find that 

 the space which they passed over from north to south on the earth, 

 was proportional to the change of place of the horizon in the celestial 

 sphere ; and as the horizon is, at every place, in the direction of the 

 earth's apparently level surface, this observation would naturally sug- 

 gest to them the opinion that the earth is placed within the celestial 

 sphere, as a small globe in the middle of a much larger one. 



We find this doctrine so distinctly insisted on by Aristotle, that we 

 may almost look on him as the establisher of it. 49 " As to the figure of 

 the earth, it must necessarily be spherical." This he proves, first by 

 the tendency of things, in all places, downwards. He then adds, 50 

 "And, moreover, from the phenomena according to the sense: for if 

 it were not so, the eclipses of the moon would not have such sections 

 as they have. For in the configurations in the course of a month, the 

 deficient part takes all different shapes ; it is straight, and concave, and 

 convex ; but in eclipses it always has the line of division convex ; 

 wherefore, since the moon is eclipsed in consequence of the interposi- 

 tion of the earth, the periphery of the earth must be the cause of this 

 by having a spherical form. And again, from the appearances of the 

 stars, it is clear, not only that the earth is round, but that its size is 

 not very large : for when we make a small removal to the south or the 

 north the circle of the horizon becomes palpably different, so that the 

 stars overhead undergo a great change, and are not the same to those 

 that travel to the north and to the south. For some stars are seen in 

 Egypt or at Cyprus, but are not seen in the countries to the north of 

 these ; and the stars that in the north are visible while they make a 

 complete circuit, there undergo a setting. So that from this it is 

 manifest, not only that the form of the earth is round, but also that it 

 is a part of not a very large sphere : for otherwise the difference would 

 not be so obvious to persons making so small a change of place. 

 Wherefore we may judge that those persons who connect the region in 

 the neighborhood of the pillars of Hercules with that towards India, 

 and who assert that in this way the sea is one, do not assert things 

 very improbable. They confirm this conjecture moreover by the 



49 Arist. de Ccelo, lib. ii. cap. xiv. ed. Casaub. p. 290. 50 p. 291 C. 



