354 POPULAR LECTURES AND ADDRESSES. 



servers at South Shetland, just within the 

 Antarctic circle. This would be something like 

 four feet of snow and rainfall. (I am sorry I must 

 give you results not always in metres or centi- 

 metres : easy things made difficult is the result of 

 the English system of weights and measures.) I 

 find, then, that with the viscosity taken from Main's 

 observation, the thickness of the ice sheet at the 

 South Pole would be 5,300 metres, that is about 

 18,000 feet. It is a very considerable thick- 

 ness about three miles but only a quarter of 

 Croll's estimate, which is much too high. The 

 ice could not possibly stand on the Antarctic 

 continent at a height of twelve miles. 



Questions as to the possible effect of this 

 Antarctic ice-sheet, or of changes in respect to its 

 thickness, would be much too serious for me t<> 

 enter upon just now. There arc just two or three 

 points I would like to consider. The amount of 

 viscosity, and the probable slope of the Antarctic 

 Continent, seemed to show that the ice cannot be 

 very much thicker than 2,000 or 3,000 feet, and not 

 nearly so much as 5,000 metres, as I have estimated 



