460 . KEPOET — 1881. 



Belirmg Strait, having at least double the volume of the Atlantic 

 counter-currents, would bring the iceberg-limit in eastern Asia as far 

 south as Pekin ^ (40° lat.), and cover the valley of the Amoor and the 

 northern Japanese islands with a coating of glacial ice.^ 



The destruction of vegetation caused by the Kuro-Siwo counter- 

 currents would be far more than equivalent to the small benefits obtained 

 in January temperatures from its admission to the Arctic regions. 



Prop. III. — It is required to calculate the effects upon climate of an 

 ocean-current admitted to the Arctic Ocean from tlie Indian Ocean, across 

 the Casjjian and Aral Sea depression, to the east of the Ural Mountain-chain 

 and Nova Zemhla. 



This ocean-current has been suggested by Mr. Alfred R. "Wallace as a 

 probable cause of recent changes in climate, and is highly probable on 

 geological grounds. 



The mean width of the Indian Ocean, in tropical latitudes, as com- 

 pared with that of the Atlantic Ocean, is as 520 to 625. The mean 

 annual temperatures of the air in the Indian Ocean are — 



Korth Indian Ocean. 



Mean . 80°-5.S 



The vapour-tension corresponding to this temperature is 1*035 in. 

 Hence, following the same method as before, we find the ratio of 

 volumes of 



IST. Indian Ocean current 520 1001 A.oAt; 



N, Atlantic Ocean current 625 1035 



The relative thermal (ice-melting) effects of the two currents will be 

 found by multiplying by the excess of temperatures above the freezing- 

 point, or 



80°-53 F. - 32°-0 F. ^ 48-53 



79°-38 F. - 32°-0 F. "" 47-38 



This gives, finally, for the ratio of the thermal effects : — 



JN". Indian Ocean ^ oak , 48-53 r, on, 



--— — - — -— = 0-805 X -r^Ti^ = 0-824. 



N. Atlantic Ocean 47-38 



Hence we may conclude that the supposed North Indian Ocean current, 

 both in volume and thermal efiect, would amount to about four-fifths of 

 the px'esent Gulf Stream, whereas the North Pacific Ocean current would 

 have five-fourths of the thermal effect of the Gulf Stream and two and a 



' If the Labrador counter-current were twice its present volume, it is highly 

 probable (if North America were at the same time depressed a few hundred feet) 

 that the limit of the edge of ice in spring would reach the latitude of New York, and 

 that all the glacial phenomena of that continent would be reproduced. 



- The absence of all traces of glaciation or of ice-transport of boulders in the 

 Altai Mountain ranges, and indeed throughout Eastern Siberia, renders it highly 

 probable that Behring Strait was not widened and deepened in recent Geological 

 times, although it has often been dry land. 



