POLAR ICE-CAPS AND SEA LEVELS. 329 



theory of stability is really so clear that it is a 

 wonder Laplace did not see it straight away. But 

 he was so intensely mathematical that he often did 

 not see the simplicity of the results which he 

 attained by complicated mathematical analysis. 

 Suppose you shift a quantity of ice from one place 

 to another on the globe ; and suppose, instead of 



FIG. 4. 



sea-water of its actual density, we had ideal water 

 of a twentieth part of the density of sea-water, then 

 the attraction of this solid mass of ice upon the 

 water would be calculated simply by the attraction 

 of the ice upon the ideal water. The figure would 

 be such that the surface of the ideal water would 

 be everywhere perpendicular to the surface of the 



