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period, what was the use of such evidence ? The very moraines might 

 have been produced by the glaciers which had strewn even our own 

 country with erratic boulders and glacial ddbris. Again, it was no un- 

 common thing in Iceland for huge masses of glaciers to slide down the 

 mountain side during periods of eruption, scratching the harder and 

 furrowing the softer rocks in their progress, and leaving heaps of 

 ddbris in no way distinguishable from terminal moraines. These facts 

 were rather startling. Tiiie, the glaciers of Iceland might, and, no 

 doubt, did ebb and flow, but they gained upon the whole, and never 

 would increase to that extent was not the annual accumulation vastly 

 in excess of the waste. This might be due to a cycle of unpropitious 

 seasons. Possibly. But they found this advance of northern glaciers 

 was not peculiar to Iceland. Dr. Nordinskjold had proved a consider- 

 able advance in the glaciers of Spitzbergen ; Greenland gave us the 

 same intelligence. This seemed to point to something more than a 

 local advance, compensated for by a retreat in other places. It was 

 too rapid an advance to be accounted for by astronomical causes. But 

 could not they suggest some comparatively slight physical changes 

 which might account for it ? 



Granted, that above a certain latitude the earth only received as 

 much heat during the summer as it did during the winter, and that in 

 one winter it would accumulate just as much snow and ice as the 

 summer's heat would suffice to melt, if it were all employed for that 

 purpose. Now, they were perfectly aware that snow and ice having 

 once accumulated, a greater part of the succeeding summer's heat 

 would be reflected back into space and not employed in melting the 

 snow and ice, while the aqueous vapours condensing above it would 

 screen the snow from solar influence. Thus a new glacial period 

 would creep upon us, heralding its approach by an advance band of 

 low temperature of its own production were it not for the warm oceanic 

 and atmospheric currents, the beneficial influence of which we had 

 only to look at the varying temperature of many localities in similar 

 latitudes to appreciate. 



A great alteration in temperature and climate would certainly 

 take place, supposing any variation should occur in the direction of 

 these currents — in the Gulf Stream, for instance. Supposing that its 

 waters instead of reaching so far north, were deflected southwards, 

 then not only would Arctic climates and Arctic ice be less affected by 



