ASTRONOMY of the BRAHMINS. i8i 



that appears in the former to have been univerfally eflablifhed, 

 viz. that their orbits were circles, having the earth within 

 them, but removed at a fmall diftance fronr the centre, and 

 that each planet defcribed the circumference of its orbit, not 

 with an uniform velocity, but with one that would appear uni- 

 form, if it were viewed from a point as far above the centre of 

 the orbit, as that centre is above the earth. This point was, in 

 the language of Ptolemy's aftronomy, the centre of the 

 Equant. 



Now, concerning this coincidence, it is the more difficult to 

 judge, as, on the one hand, it cannot be afcribed to accident, 

 and, on the other, it may be doubted, whether it arifes necef- 

 farily out of the nature of the fubjedl, or is a confequence of 

 fome unknown communication between the aftronomers of 

 India and of Greece. 



The firft hypothefis by which men endeavoured to explain 

 the phenomena of the celeftial motions, was that of a uniform 

 motion in a circle, which had the earth for its centre. This 

 hypothefis was, however, of no longer continuance than till 

 inftruments of tolerable exadtnefs were directed to the heavens. 

 It was then immediately difcovered, that the earth was not the 

 centre of this uniform motion ; and the earth was therefore 

 fuppofed to be placed at a certain diftance from the centre of 

 the orbit, while the planet revolved in the circumference of it 

 with the fame velocity as before. Both thefe ftep^may be ac- 

 counted neceffary ; and in however many places of the earth, 

 and however cut off from mutual intercourfe, aftronomy had 

 begun to be cultivated, I have no doubt that thefe two fuppo- 

 fitions would have fucceeded one another, juft as they did 

 among the Greek aftronomers. 



But when more accurate obfervations had fhewn the infuffi- 

 ciency even of thig fecond hypothefis, what ought naturally to 

 be the third, may be thought not quite fo obvious ; and if the 

 Greeks made choice of that which has been defcribed above, it 



may 



