114 DISCUSSIONS IN CLIMATOLOGY. 



southern. Another result which follows, as has also 

 been shown, is that the great equatorial currents are 

 made to lie at some distance to the north of the 

 equator ; hence, when they are impelled against the 

 American and the Asiatic continents, and become 

 deflected northwards and southwards, the larger por- 

 tion of the water goes to the north, and thus raises 

 the temperature of the northern hemisphere. Now, if 

 all this results as a consequence from the present small 

 amount of eccentricity, how much greater must have 

 been the effect during the glacial epoch, when the 

 eccentricity was more than three times its present 

 value, and the southern winter also, as now, in aphelion ! 

 All those effects which we have just been considering 

 would then have been magnified far more than three- 

 fold. 



Climatic Conditions of the Two Hemispheres the 

 Reverse 10,000 or 12,000 years ago : Argument from. 

 — Ten or twelve thousand years ago, when our northern 

 winter solstice was last in aphelion, the climatic con- 

 ditions were in all probability the reverse of what they 

 are at present. There appears to be pretty good 

 geological evidence that such was the case. This, 

 under the present small amount of eccentricity, shows 

 not only to what an extent climate is affected by 

 eccentricity, but also (and with this we are at present 

 more particularly concerned) that its tendency is to 

 cool the one hemisphere and warm the other, to 

 accumulate the snow and ice on the one and melt 

 them on the other. And this result, to a large extent, 

 is doubtless brought about by its influence on ocean- 

 currents. 



There are good reasons for concluding, as Professor 

 J. Geikie has fully shown,* that at a very recent date 



* " Prehistoric Europe," p. 411. 



