§ 154, 155. GULF STREAINI, CLIMATES, AND COMMERCE. 5I 



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 Liver- 

 pool, on the other side, though 2° farther north, being closed with 

 ice, even in the dead of winter ? 



154. The Thermal Chart (Plate TV.) shows this. The isother- 

 Miidness of an Ork- ^al liucs of 60°, 50°, ctc. Starting off from the par- 

 ney winter. ^HqI ^f 40° ^car the coasts of the United States, run 

 off in a northeastwardly direction, showing the same oceanic tem- 

 perature on the European side of the Atlantic in latitude 55° or 

 60°, that we have on the western side in latitude 40°. Scott, in 

 one of his beautiful novels, tells us that the ponds in the Orkneys 

 (latitude near 60°) are not frozen in winter. The people there 

 owe their soft climate to this grand heating apparatus, for drift- 

 wood from the West Indies is occasionally cast ashore there by 

 the Gulf Stream. 



155. Nor do the beneficial influences of this stream upon cli- 

 Amountofheatdai- mate cud hcrc. The West Indian Archipelago is 



ly escaping through , -ii-i i- n • ^ 1 



the Gulf Stream. eucompassed on one side by its chain 01 islands, 

 and on the other by the Cordilleras of the x\ndes, contracting 

 with 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 of perpetual snow, and 

 descend first into the iierra iemplada, 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 of aqueous circulation, the 

 peculiar features of the surrounding country assure us we should 

 have the hottest, if not the most pestilential climate in the world. 

 As the waters in these two caldrons become heated, they are 

 borne off by the Gulf Stream, and are replaced by cooler currents 

 through the Caribbean Sea ; the surface w^ater, as it enters here, 

 being 3° or 4°, and that in depth even 40°* cooler than when it 

 escapes from the Gulf. Taking only this difference in surface 

 temperature as an index of the heat accumulated there, a simple 

 calculation will show that the quantity of heat daily carried off 



* Temperature of the Caribbean Sea (from the journals of Mr. Dunsterville) : 

 Surface temperature : 83°, September; 84°, July; 83°-86^-°, Mosquito Coast. 

 Temperature in depth: 48°, 240 fathoms; 43°, 380 fathoms; 42°, 450 fathoms; 

 43°, 500 fathoms. 



