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species should be both finite and infinite in the 

 same thing, is impossible. 



THEOREM 7. 



Simple bodies are terminated according to spe- 

 cies. 



Demonstration. For let the magnitude A be a 

 simple body. Since, therefore, a simple body is 

 moved with a simple motion, A will be moved with 

 a simple motion. And if it is moved in a circle, it 

 will have one nature and one form. But if it is 

 moved according to any one of the motions in a 

 right line, if it is moved from the middle only, it 

 will be fire, but if only to the middle, earth. But, 

 if it is light with respect to one thing, and heavy 

 with respect to another, it will be some one of the 

 middle elements. The species therefore of simple 

 bodies are terminated. 



THEOREM 8. 



Time is continued and perpetual. 



Demonstration. For, if it is neither continued 

 nor eternal, it will have a certain beginning. Let, 

 therefore, A B be time, and let its beginning be A. 

 But if A is time, it is divisible, and we shall not 

 yet have the beginning of time, but there will be 

 another beginning of the beginning. But, if A is 



