54 THE PHYSICAL GEOGRAPHY OF THE SEA. 



69. These cold waters doubtless come down from the north to 

 replace the warm water sent through the Gulf Stream to mod- 

 erate the cold of Spitzbergen ; for within the Arctic Circle the 

 temperature at corresj^onding depths off the shores of that island 

 is said to be only one degree Colder than in the Caribbean Sea, 

 while on the coasts of Labrador and in the Polar Seas the tem- 

 perature 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 eight- 

 een 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 cur- 

 rents on their way to the tropical regions, which they are intend- 

 ed to cool. One has been found at the equator (§ 23) two hundred 

 miles broad and 23° colder than the surface water. Unless the 

 land or shoals intervene, it no doubt comes down in a spiral curve, 

 approaching in its course the great circle route. 



70. Perhaps the best indication as to these cold currents may 

 be derived from the fish of the sea. The whales first pointed out 

 the existence of the Gulf Stream by avoiding its warm waters. 

 Along our own coasts, all those delicate animals and marine pro- 

 ductions which delight in warmer waters are wanting ; thus indi- 

 cating, by their absence, the cold current from the north now 

 known to exist tliere. In the genial warmth of the sea about the 

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

 abundance, those delicate shell-fish and coral formations which are 

 altogether wanting in the same latitudes along the shores of South 

 Carolina. The same obtains in the west coast of South America ; 

 for there the cold current almost reaches the line before the first 

 sprig of coral is found to grow. 



71. A few years ago, great numbers of bonita and albercore — 

 tropical fish — following the Gulf Stream, entered the English 

 Channel, and alarmed the fishermen of Cornwall and Devonshire 

 by the Imvoc which they created among the pilchards there. 



