ITS EARLIEST STAGES. 161 



of the earth's apparently level surface, this obser- 

 vation would naturally suggest 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 40 . "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 con- 

 figurations 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 



49 Arist. de Ccelo. Lib. ii. cap. xiv. ed. Casaub. p. 290. 



50 p. 291 C. 



VOL. I. M 



