GULF STREAM, CLI3IATES, AND COMMERCE. 57 



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°. Another cast wdth three hundred and 

 eightj-six fathoms gave 43° below against 83° at the surface. 

 The hurricanes of those regions agitate the sea to great de2:)ths ; 

 tliat of 1780 tore rocks up from the bottom seven fathoms deep, 

 and cast them ashore. They therefore cannot fail to bring to the 

 surface portions of the cooler water below. 



157. Cold water at the bottom of the Gulf Stream. — At the very 

 bottom of the Gulf Stream, when its surface temperature was 80°, 

 the deep-sea thermometer of the Coast Sui-vey 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 Spitz - 

 bergen ; for within the Arctic Circle the temperature at corre- 

 sponding depths off the shores of that island is said to be only 

 one degree colder than in the Caribbean Sea, while on the shores 

 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 fresh-water ice. Captain 

 Scoresby relates, that on the coast of Greenland, in latitude 72°, 

 the temperature of the air was 42° ; of the water, 34° ; and 29° 

 at the depth of one hundred and eighteen fathoms. He there 

 found a surface current setting to the south, and bearing with it 

 this extremely cold water, with vast numbers of icebergs, whose 

 centres, perhaps, were far below zero. It would be curious to 

 ascertain the routes of these under-currents on their way to the 

 tropical regions, which they are intended to cool. One has been 

 found at the equator (§ 97) two hundred miles broad and 23*^ 

 colder than the surface water. Unless the land or shoals inter- 

 vene, it no doubt comes down in a spiral curve ('§ 96), approach- 

 ing in its course the great circle route. 



158. Fish and currents. — Perhaps the best indication as to these 

 cold currents may be derived from the fish of the sea. The 

 whales, by avoiding its warm waters, pointed out to the fisher- 

 man the existence of the Gulf Stream. Along our own coasts, 

 all those delicate animals and marine productions which delight 

 in warmer waters are wanting ; thus indicating, by their absence, 

 the prevalence of the cold current from the north now known to 

 exist there. In the genial warmth of the sea about the Bermudas 

 on one hand, and Africa on the other, we find, in great abundance. 



