52 THE PHYSICAL GEOGRAPHY OF THE SEA. 



bj the Gulf Stream from those regions, and discharged over the 

 Atlantic, is sufficient to raise mountains of iron from zero to the 

 melting point, and to keep in flow from them a molten stream of 

 metal greater in volume than the waters daily discharged from 

 the Mississippi Kiver. 



156. Who, therefore, can calculate the Benign influence of this 

 Its benign influences, woudcrful currcut upou the climatc of the South ? 

 In the pursuit of this subject, the mind is led from nature up to 

 the great Architect of nature ; and what mind will the study of 

 this subject not fill with profitable emotions ? Unchanged and 

 unchanging alone, of all created things, the ocean is the great em- 

 blem of its everlasting Creator. " He treadeth upon the waves 

 of the sea," and is seen in the wonders of the deep. Yea, " He 

 calleth for its waters, and poureth them out upon the face of the 

 earth." In obedience to this call, the aqueous portion of our 

 planet preserves its beautiful system of circulation. By it heat 

 and warmth are dispensed to the extra-tropical regions ; clouds 

 and rain are sent to refresh the dry land; and by it cooling 

 streams are brought from Polar Seas to temper the heat of the 

 torrid zone. At the depth of two hundred and forty fathoms, the 

 temperature of the currents setting into the Caribbean Sea has 

 been found as low as 48'^, while that of the surface was 85°. An- 

 other cast with three hundred and eighty-six fathoms gave 43° be- 

 low against 83° at the surface. The hurricanes of those regions 

 agitate the sea to great depths ; that of 1780 tore rocks up from the 

 bottom seven fathoms deep, and cast them ashore. They there- 

 fore can not fail to bring to the surface portions of the cooler wa- 

 ter below. 



157. At the very bottom of the Gulf Stream, when its surface 

 Cold water at the tcmpcraturc was 80°, the deep-sea thermometer of 



bottom of the Gulf , ^ ^ ■, ^ -, 



Stream. the Coast Survcy has recorded a temperature as 



low as 35° Fahrenheit. These cold waters doubtless come down 

 from the north to replace the warm water sent through the Gulf 

 Stream to moderate the cold of Spitzbergen ; for within the Arc- 

 tic Circle the temperature at corresponding depths off the shores 

 of that island is said to be only one degree colder than in the Car- 

 ibbean Sea, while on the coasts of Labrador and in the Polar Seas 

 the temperature of the water beneath the ice was invariably found 

 by Lieutenant De Haven at 28°, or 4° below the melting point of 



