PROGRESS OF MODERN ASTRONOMY 



tricity of the orbits of the planets and of the satellites; 

 and, finally, the great eccentricity of the orbits of the 

 comets, as if their inclinations had been left to chance. 



" Buff on is the only man I know who, since the dis- 

 covery of the true system of the world, has endeavored 

 to show the origin of the planets and their satellites. 

 He supposes that a comet, in falling into the sun, drove 

 from it a mass of matter which was reassembled at a 

 distance in the form of- various globes more or less 

 large, and more or less removed from the sun, and that 

 these globes, becoming opaque and solid, are now the 

 planets and their satellites. 



"This hypothesis satisfies the first of the five pre- 

 ceding phenomena; for it is clear that all the bodies 

 thus formed would move very nearly in the plane 

 which passed through the centre of the sun, and in the 

 direction of the torrent of matter which was produced ; 

 but the four other phenomena appear to be inexplicable 

 to me by this means. Indeed, the absolute move- 

 ment of the molecules of a planet ought then to be in 

 the direction of the movement of its centre of gravity ; 

 but it does not at all follow that the motion of the ro- 

 tation of the planets should be in the same direction. 

 Thus the earth should rotate from east to west, but 

 nevertheless the absolute movement of its molecules 

 should be from east to west; and this ought also to 

 apply to the movement of the revolution of the satel- 

 . in which the direction, according to the hypoth- 

 which he offers, is not necessarily the same as that 

 of the progressive movement of the planets. 



henomenon not only very difficult to explain 

 under this hypothesis, but one which is even contrary 



33 



