Oil Natural and Moj^al Philosophic, S8;> 



one and the same to all, they each move in 

 elliptic orbits, and two properties, viz. that the 

 elliptic areas commencing from the pcrHielion 

 or aj)hclif)n of each are constantly in proportion 

 to the timei elapsed, and that the cubes of the 

 distances of the planets from the sun are as tt^e 

 squares of their periodical revolutions iii their 

 orbits, harmonise the motions of them all, 

 and assign to each of them, and to their inha- 

 bit^mts their respective order and proportion of 

 days and nights and seasons. No account can 

 be given of this uniformity and harmony, but 

 in one of these two ways, first, that some pow- 

 erful agent is continually acting upon each orb, 

 so as to give to each that direction and velocitv 

 which his will determines. I'his is not sup- 

 posed by any one, -not even by those, who ac- 

 knowledge this agent as the primary cause. 

 The second, therefore, as of Tiecessity presents 

 itself, that each planet has impressed upon it a 

 common pro})crty or properties, which may be 

 considered as their common constitution, from 

 which are constantly derived the uniformity and 

 harmony of their motions. 



We have then advanced a considerable step 

 farther, we.have taken into our view, and sub- 

 mitted to our examination, inasmuch as thev 

 can be subjected thereto, the innumerable 

 worlds that float in the vast expanse. Though 



