ON TEE EFFECTS OF OCEANIC CURRENTS UPON CLIMATES. 4G1 



half times its volume, which latter determines the amount and volume of 

 the counter- cui'rent of cold water. 



If we calculate from Ferrel's Tables, as before the effect of the new 

 North Indian Ocean current, reckoned as four-fifths of the Gulf Stream, 

 wo find as follows : — • 



Latitude 60°. — It will raise the January temperature, from 70° E. long, 

 to 102° E. long., from - 10°-0 F. to + 32°-8 P. ; which is equivalent to a 

 rise at all longitudes from + 6°-16 F. to + 8°-53 F. 



Latitude 70°. — It will raise the January temperature, from 80° B. long, 

 to 104° B. long., from - 18°-33 F. to + 20°-75 F. ; which is equivalent to 

 a rise at all longitudes from - ll°-53 F. to - 9°-36 F. 



Latitude 80°. — It will raise the January temperature, from 90° E. long, 

 to 130° B. long., from - 27°-4 F. to - 10°-44 F., which is equivalent to a 

 rise at all longitudes from — 21°-87 F. to - 20°-3 F. 



If we bring together, into one point of view, all the preceding results, 

 we find the following changes of winter climate produced in the Arctic 

 regions by the successive introduction of the Gulf Stream, the Knro-Siwo 

 (North Pacific Stream), and the North Indian Ocean Stream. 



{A") Tem^jcratures before Admission of the Gulf Stream. 



(Z)) Temperatures after admitting the Xorth Indian Ocean Stream, to the cast of the 

 Ural Chain, through the Caspian Sea depression. 



Lat. July Mean January Range 



60° . 57°-0 F. . 32° 76 F. . - 8°-53 F. . 48°-47 P. 



70° . 44°-3 . 17°-47 . - g-'-SS . 53°-65 



80° . 34°-l . 6°-9 . - 20°-3 . 54°-4 



After all the tepid ocean-streams are admitted, it is plain that the 

 Arctic regions would still remain very uncomfortable quarters for either 

 plants or animals. Further, if the admission of the North Indian Ocean 

 current through the Caspian were accompanied by a depression of 

 Northern Europe through some hundred feet, its counter- current would 

 act under most favourable circumstances for lowering the July tempera- 

 ture of Europe, and might even produce all the known glacial phenomena 

 of Scandinavia, the British Islands, Switzerland, aiid the Pyrenees. 



Corollary. — The magnitude of a glacier, ccderis ]_-iarihus, depends upon 

 that of the snow-field in which it takes its origin ; and any depression of 

 the line of perpetual snow will increase the magnitude of the snow-field 

 and glaciers. 



