CAUSE OF MILD POLAR CLIMATES. 155 



during that period, is not such as to enable me to form 

 any opinion whatever either as to the probability or 

 to the improbability of the existence of such channels 

 as are assumed by Mr. Wallace. But, looking at the 

 question from a physical point of view, it seems to me 

 pretty evident that if such channels as he supposes 

 existed, allowing of a continuous flow of equatorial 

 water into the Arctic seas, it would certainly prevent 

 the formation of permanent ice around the Pole, and 

 would doubtless confer on the Arctic regions a mild 

 and equable climate. This would be more particularly 

 the case if, as Mr. Wallace supposes, owing to geo- 

 graphical conditions, far more of the equatorial water 

 was deflected into the Arctic than into the Antarctic 

 regions. 



But, at the same time, I think it is just as evident 

 that these channels would not neutralise the effects 

 resulting from a high state of eccentricity. It may 

 be quite true that the physical causes, brought into 

 operation during a high state of eccentricity, might 

 not be sufficient to reduce the quantity of warm water 

 flowing into the Arctic Ocean to an extent that would 

 permit of the formation of permanent ice around the 

 Pole, but it certainly would greatly diminish the flow 

 into the Arctic Ocean. Supposing that, at the com- 

 mencement of the last Glacial Epoch, the volume of 

 the Gulf Stream was double what it is at present, this 

 condition of things would not have prevented the 

 operation of those physical agents which brought 

 about the Glacial Epoch, although it no doubt would 

 have considerably modified the severity of the glacia- 

 tion resulting from their operation. The very same 

 thing would hold true, though perhaps in a much 

 greater degree, in reference to the channels assumed 

 by Mr. Wallace. 



