POLAR ICE NOT DUE TO ELEVATION. 79 



reached the inner parts would produce far less snow 

 than would be melted by the long hot days of 

 summer." * 



This opinion, that the mass of ice is probably greatest 

 at the outer rim, which of course is most exposed to 

 moist winds, and that it gradually becomes less and 

 less as we proceed inwards till at last it disappears 

 altogether, is by no means an uncommon one. 



It was to establish this conclusion that Professor 

 Nordenskj bid's famous expedition over the ice of 

 Greenland was undertaken. 



It by no means follows, as some might be apt to 

 suppose, that the ice must be thickest where the 

 snowfall is greatest. In the case of continental ice, 

 the greatest thickness must always be at the centre 

 of dispersion ; but it is here that, owing to distance 

 from the ocean, the snowfall is likely to be least. 



We have no reason to believe that the quantity of 

 snow falling, at least at the South Pole, is not con- 

 siderable. Lieut. Wilkes estimated the snowfall of the 

 Antarctic regions to be about 30 feet per annum ; and 

 Sir John Ross says that during a whole month they 

 had only three days free from snow. But there is one 

 circumstance which must tend to make the snowfall 

 near the South Pole considerable, and that is the 

 inflow of moist winds in all directions towards it ; and 

 as the area on which these currents deposit their snow 

 becomes less and less as the Pole is reached, this must, 

 to a corresponding extent, increase the quantity of 

 snow falling on a given area. Let us assume, for 

 example, that the clouds in passing from lat. 60° to 

 lat. 80° deposit moisture sufficient to produce, say, 

 30 feet of snow per annum, and supposing that by the 

 time they reach lat. 80° they are in possession of only 



* " Island Life," p. 156. 



