A HISTORY OF SCIENCE 



Dr. Croll argues that a slight change in the relative 

 values of northern and southern trade-winds (such as 

 he believes has taken place at various periods in the 

 past) would suffice to so alter the equatorial current 

 which now feeds the Gulf Stream that its main bulk 

 would be deflected southward instead of northward, 

 by the angle of Cape St. Roque. Thus the Gulf Stream 

 would be nipped in the bud, and, according to Dr. 

 Croll's estimates, the results would be disastrous for the 

 northern hemisphere. The anti-trades, which now are 

 warmed by the Gulf Stream, would then blow as cold 

 winds across the shores of western Europe, and in all 

 probability a glacial epoch would supervene through- 

 out the northern hemisphere. 



The same consequences, so far as Europe is con- 

 cerned at least, would apparently ensue were the Isth- 

 mus of Panama to settle into the sea, allowing the 

 Caribbean current to pass into the Pacific. But the 

 geologist tells us that this isthmus rose at a compara- 

 tively recent geological period, though it is hinted that 

 there had been some time previously a temporary land 

 connection between the two continents. Are we to 

 infer, then, that the two Americas in their unions and 

 disunions have juggled with the climate of the other 

 hemisphere ? Apparently so, if the estimates made of 

 the influence of the Gulf Stream be tenable. It is a 

 far cry from Panama to Russia. Yet it seems within 

 the possibilities that the meteorologist may learn from 

 the geologist of Central America something that will 

 enable him to explain to the paleontologist of Europe 

 how it chanced that at one time the mammoth and 

 rhinoceros roamed across northern Siberia, while at 



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