AND THEORY OF THE HEAVENS. 89 



or at least are rare, where only a few cometary bodies 

 have been formed, and where the movements of the 

 elementary matter has not been fitted to attain to 

 regulated equilibrium with the central forces as in the 

 region near the centre, but issue in an almost universal 

 falling towards the centre and increase the sun with all 

 the matter out of such widely extended ranges of space 

 it is evident, I say, that from these causes the bulk 

 of the sun must attain to such a preponderating greatness 

 of mass. 



But in order to compare the planets with each other 

 as regards their masses, we remark, first, that according 

 to the mode of their formation as above indicated, the 

 quantity of the matter which comes to compose a planet 

 depends chiefly on its distance from the sun: (i) because 

 the sun by its attraction limits the sphere of the attrac- 

 tion of a planet, but under similar circumstances it does 

 not limit the more distant ones so strictly as those that 

 are near ; (2) because the circles out of which all the 

 particles are derived to make up a planet, are described 

 with a greater radius, and therefore contain more 

 elementary matter within them, than the smaller circles ; 

 (3) because, for the reason now stated, the breadth be- 

 tween the two planes of greatest divergence in an angle 

 of the same number of degrees is greater at great dis- 

 tances than at small. On the other hand, this advantage 

 of the more distant planets over the inferior planets is 

 limited by the fact that the particles nearer the sun will 

 be of a denser kind and according to all appearance 

 also be less scattered than those at a greater distance. 

 But it may likewise be easily inferred that the former 

 advantages do nevertheless far outstrip the latter limita- 



