140 On the Formation of the Universe. 



fluid or aerial ; for, being destitute of an equilibrium, the 

 mutual attraction of its parts would immediately have redu- 

 ced it to a spherical figure. But suppose the matter con- 

 tained in Saturn and its ring, when condensing from an ae- 

 rial state, had been retained by the force of its satellites, in 

 the form of a flat spheroid ; it would gradually stiffen by the 

 expulsion of light and heat, and most rapidly at the edge on 

 account of its tenuity. Eventually the edge, by reason of 

 its greater increase of density, and excess of velocity above 

 what would keep a satellite at its distance from the centre, 

 would be abandoned by the interior part of the wheel, and 

 form a ring around it. The slender edge of the planet, as 

 soon as released from its connexion with the ring, would 

 fall into the planet, and inevitably produce a depression 

 about its equator. The planet being in a plastic state, could 

 not restore itself to the form which it would naturally as- 

 sume if it were fluid ; so that it must still remain at least in 

 some degree depressed about its equator. Such is Saturn's 

 form in reality. Astronomers have accounted for the forms 

 of all the other bodies in the system, by the principles of 

 gravitation. This stands a single anomaly, and by all the 

 principles of gravitation and motion in which it is now con- 

 cerned, it is wholly inexplicable. If we suppose half the 

 quantity of matter contained in the ring of Saturn to be sol- 

 id, and perfectly regular, and the other half to be fluid, the 

 fluid parts having an attraction for each other, the lateral per- 

 pendicular action of the solid part could do nothing to pre- 

 vent accumulations from commencing, and when they had 

 once commenced, they would unavoidably continue, till the 

 whole would be collected together ; and the most of the 

 solid part, being much more distant from the fluid parts, 

 than the fluid parts from each other, its comparative action 

 would of course be feeble. From this example it is easy 

 for the mind to perceive, that however small the fluid part 

 might be, it would have a similar tendency to accumulate in 

 a degree proportioned to its quantity. If the ring, after its 

 formation, remained entirely regular, the least bias possible, 

 af. La Place has shown, would destroy its balance, and it 

 would be certainly and inseparably attached to the planet. 

 For if the planet P, fig. 3, receive a bias toward the parts of 

 the regular concentric ring m n r s, the parts m, n, r, hav- 

 ing the sarjie force as s, could not by revolving change the 



