178 COSMICAL ARRANGEMENTS. 



appears by the preceding reasoning, that in this 

 case, if there were to be any disturbance either 

 of the solid or fluid parts, the solid parts would 

 rise from the centre of the watery sphere as far as 

 they could : that is, all the water would run to 

 one side and leave the land on the other. Such 

 an ocean would be in unstable equilibrium. 



Now a question naturally occurs, is the equi- 

 librium of our present ocean of this unstable 

 kind, or is it stable ? The sea, after its most 

 violent agitations, appears to return to its former 

 state of repose ; but may not some extraordinary 

 cause produce in it some derangement which 

 may go on increasing till the waters all rush one 

 way, and thus drown the highest mountains? 

 And if we are safe from this danger, what are 

 the conditions by which we are so secured ? 



The illustration which we have employed 

 obviously suggests the answer to this question ; 

 namely, that the equilibrium is unstable, so long 

 as the solid parts are of such a kind as to float in 

 the fluid parts ; and of course we should expect 

 that the equilibrium will be stable whenever the 

 contrary is the case, that is, when the solid parts 

 of the earth are of greater specific gravity than 

 the sea. A more systematic mathematical cal- 

 culation has conducted Laplace to a demonstra- 

 tion of this result. 



The mean specific gravity of the earth appears 

 to be about five times that of water, so that the 



