BOOK II. xin. 69-71 



their morning rising, because in that state their 

 aceeleration first begins to diminish, but in their first 

 stations their altitude also is ascended, since then the 

 numbers first begin to be reduced and the stars begin 

 to recede. The reason for this must especially be 

 given. When struck in the degree that we stated 

 and by a triangular ray of the sun they are prevented 

 from pursuing a straight course, and are hfted 

 upward by the fiery force. This cannot be directly 

 perceived by our sight, and therefore they are 

 thought to be stationary, which has given rise to the 

 term ' station.' Then the violent force of the same 

 ray advances and compels them by the impact of the 

 heat to retire. This occurs much more at their 

 evening rising, when they are driven out to the top 

 of their apsides by the full opposing force of the sun, 

 and appear very small because they are at the 

 distance of their greatest altitude and are moving 

 with their smallest velocity — which is pi-oportionately 

 smaller when this occurs in the highest signs of their 

 apsides. From their evening rise their altitude is 

 descended with a velocity now decelerating less and 

 less, but not accelerating before their second stations, 

 when their altitude also is descended, the ray passing 

 above thera from the other side and pressing them 

 down again to the earth with the same force as that 

 with which it had raised them to the sky from the 

 former triangle. So much difference does it make 

 whether the rays come from below or from above, 

 and the same things occur far more in the evening 

 setting. 



This is the theory of the higher stars ; that of 

 the rest is more difficult and has been explained by 

 nobody before ourselves. 



217 



