182 REMARKS on tbt 



may feem to have been owing to certain metaphyfical notion* 

 concerning the fimplicity and perfection of a circular and uni- 

 form motion, which inclined them to recede from that fuppo- 

 fition, no farther than appearances rendered abfolutely necef- 

 fary. The fame coincidence between the ideas of metaphyfics 

 and aftronomy, cannot be fuppofed to have taken place in- 

 other countries ; and therefore, where we find this third hypo- 

 thefis to have prevailed, we may conclude that it was borrowed 

 from the Greeks. 



57. Though it cannot be denied, that, in this reafoning, there 

 is fome weight, yet it muft be obferved, that the introduction 

 of the third hypothecs did not reft among the Greeks altoge- 

 ther on the coincidence above mentioned. It was one fuited to 

 their progrefs in mathematical knowledge, and offered almoft 

 the only fyftem, after the two former were exploded, which 

 rendered the planetary motions the fubject of geometrical rea- 

 foning, to men little verfed in the methods of approximation. 

 This was the circumftance then, which, more than any other, 

 probably influenced them in the choice of this hypothefis, 

 though we are not to look for it as an argument ftated in their 

 works, but may judge of the influence it had, from the fre- 

 quency with which, many ages afterwards, the aysaiysT^trnt 

 of Kepler's fyftem was objected to him by his adverfaries ; an 

 objection to which that great man feemed to pay more attention 

 than it deferved. 



There is reafon therefore to think, that in every country 

 where aftronomy and geometry had neither of them advanced 

 beyond a certain point, the hypothefis of the equant would fuc- 

 ceed to that of a fimple eccentric orbit, and therefore cannot 

 be admitted as a proof, that the different fyftems in which it 

 makes a part, are neceffarily derived from the fame fource. 

 Some other circumftances attending this hypothefis, as it is 

 found in the Indian tables, go ftill farther, and feem quite in- 

 confiftent with the fuppofition that the authors of thefe tables 



derived 



