POLAR ICE-CAPS AND SEA LEVELS. 323 



" according to the same law (that is, simple propor- 

 " tionality to sines of latitudes), and amounting at 

 " each pole to 



I - b)W 



" when / denotes the thickness of the ice-cap at the 

 " pole, i the ratio of the density of ice, and w that 

 " of sea-water to the earth's mean density ; and w 

 " the ratio of the area of ocean to the whole 

 " surface. 



" Thus, for instance, if we suppose o> = 2/3, and 

 "/ == 6,000 feet, and take 1/6 and I/5J as the 

 "densities of ice and water respectively, we find 

 " for the rise of sea-level at one pole, and depression 

 " at the other, 



- x x 6000 



3 6 



i-^xi- 



3 Si* 

 " or approximately 320 feet. 



" I shall now proceed to consider roughly what 

 " is the probable extent of submergence whichj 

 " during the glacial epoch, may have resulted from 

 " the displacement of the earth's centre of gravity 



Y 



