FOURTH CHAPTER. 



OF THE ORIGIN OF THE MOONS AND THE MOVE- 

 MENTS OF PLANETS ROUND THEIR AXES. 



THE striving of a planet to form itself out of the con- 

 tents of the elementary matter, is at the same time the 

 cause of its axial rotation, and it also produces the 

 moons that are to revolve around it. What the sun 

 with its planets is on the great scale, is represented on 

 a smaller scale by a planet which has a widely extended 

 sphere of attraction ; that is to say, it is the head of a 

 system whose members have been put into motion by 

 the attraction of the central body. The planet while 

 forming itself, in setting the particles of the primitive 

 matter into motion for its formation through the whole 

 range of its attraction, will out of all these falling 

 movements by means of their reciprocal action produce 

 circular movements, and at last such movements as result 

 in a common direction ; and part of these movements 

 will obtain the proper modification into a free circular 

 path, and by this restriction they will be found near 

 a common plane. In this space, just as the sun 

 forms the planets so do the planets form the moons, 

 when the distance of the attraction of these heavenly 



