176 On the Gulf Stream and Currents of the Sea. 



the northern winds of winter. It is the influence of this stream 

 upon climate that makes Erin the Emerald Isle of the sea, and 

 clothes the shores of Albion with evergreen robes, while in the 

 same latitude, on this side, the shores of Labrador are fast bound 

 in fetters of ice. In a valuable paper on currents,* Mr. Redfield 

 states, that in 1831, the harbor of St. John's. Newfoundland, was 

 closed with ice as late as the month of June, yet who ever heard 

 of the port of Liverpool, on the other side, though two degrees 

 further north, being closed with ice even in the depth of winter? 

 Baron Humboldt's isothermal curves shew that the genial influ- 

 ence of this current is felt in Norway, and even on the shores of 

 Spitzbergen, in the polar basin. The mere sweeping of the winds 

 over a large tract of ocean, without any such warm stream, is not 

 sufficient to produce such effects upon climate, as is fully shewn 

 by comparing the climate of Spitzbergen with that of places sim- 

 ilarly situated in the South Seas, with regard to winds and 

 water, but not with regard to currents. 



Nor do the beneficial influences of this stream upon climate end 

 here. The West Indian Archipelago is encompassed on one side 

 with its chain of islands, and on the other by the Cordilleras of 

 the Andes, bending through the Isthmus of Darien. and stretching 



themselves out over the plains of Central America and Mexico. 

 Beginning on the summit of this range, we leave the regions ot 

 perpetual snow, and descend, first into the tierra templada, and 

 then into the tierra caliente, or burning land. Descending still 

 lower, we reach both the level and the surface of the Mexican 

 seas — where, were it not for this beautiful and benign system ot 

 aqueous circulation, the peculiar features of the surrounding coun- 

 try assure us we should have the hottest, if not the most pesti- 

 lential climate in the world. As the waters of these two caldrons 

 become heated, they are borne off by the Gulf Stream, and are 

 replaced by cooler currents through the Carribbean sea — the wa- 

 ter, as it enters here, being 3° or 4° cooler at the surface than 

 when it escapes from the Gulf, and at considerable depth, being 

 as much as 40° * below the surface temperature. Taking *« 



* Am. Journal ofScience, vol. xlv., p. 203. 



t Surface temparnture, 85° Sept. 84° July. "| In the Carribbean Sea. 



Temp, in depth, 48°, 240 fathoms. 43°, 450 fathoms. I . A r 



Surface temp. 83°, 86i° M usque to shore. f From the Journal oi 



Depth, 42°, 450 fathoms 43°, 500 fathoms. I M. Dunstcrvilw- 





