FIRST CHAPTER. 



OF THE ORIGIN OF THE STRUCTURE OF THE 

 WORLD OF THE PLANETS GENERALLY AND 

 THE CAUSES OF THEIR MOTIONS. 



THE examination of the structure of the world, in regard 

 to the mutual relations which its parts have to one 

 another and by which they indicate the cause from which 

 they sprang, shows that two views may be taken which 

 are both equally probable and admissible. When, on the 

 one hand, it is considered that the six planets with their 

 nine satellites, which describe orbits around the sun as 

 their centre, all move in one direction, that, namely, 

 towards which the sun itself turns and which governs all 

 their revolutions by the force of attraction ; that their 

 orbits do not diverge from a certain common plane, 

 namely, that of the prolonged equatorial plane of the 

 sun ; and that in the case of the most distant heavenly 

 bodies belonging to the Solar world where the common 

 cause of motion ex hypothesi has not been so powerful as 

 in the neighbourhood of the centre, deviations from the 

 exactness of these determinations have taken place which 

 have a relation sufficiently explained by the want of the 

 impressed motion : when, I say, account is taken of all 

 this connection, we shall be induced to believe that a 



