AND THEORY OF THE HEAVENS. 115 



been the slower according as the latitude of the place 

 from which they ascended was higher. The ratio of their 

 specific gravity regulated the different heights to which 

 the particles ascended. But only those particles could 

 maintain the place of their distance in a constantly free 

 revolution, in whose case the distances to which they 

 were transported demanded such a central force as they 

 could sustain by the velocity which they possessed from 

 the axial rotation. The remaining particles, in so far 

 as they could not be brought to this exact relation by 

 the reciprocal action of the rest, must either be removed 

 by the excess of their motion out of the sphere of the 

 planet, or, from deficiency of it, must have been compelled 

 to fall again upon it. The particles scattered through the 

 whole extent of the sphere of the vapour, in virtue of the 

 same central laws, tended in the movement of their revolu- 

 tion to cut through the prolonged plane of the equator 

 of the planet on both sides; and as they would arrest 

 each other in this plane from both hemispheres, they would 

 accumulate there. And as I assume that the said vapours 

 are those which the planet sent up last as it cooled, all 

 the dispersed vaporous matter would be collected near 

 this plane in a not very broad space, and the spaces on 

 either side would be left empty. In this new and altered 

 direction, however, they would still continue the same 

 movement which kept them floating in free concentric 

 circular orbits. In this manner, then, the circle of vapour 

 altered its shape, which was that of a full sphere, into 

 the form of an out-spread disc which coincided exactly 

 with the equator of Saturn. But, owing to the same me- 

 chanical causes, this expanse could not but at last assume 

 the form of a Ring whose outer border was determined 



