§ 158. GULF STREMI, CLIMATES, AND COMMERCE. 53 



fresli-water ice. Captain Scoresby relates, that on tlie coast of 

 Greenland, in latitude 72°, the temperature of the air was 42° ; of 

 the water, 84° ; 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 undercurrents 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 in- 

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

 ing in its course the great circle route. 



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

 Fish and currents, be dcrivcd from the fish of the sea. The whales, 

 by avoiding its warm waters, pointed out to the fisherman the ex- 

 istence of the Gulf Stream. Along our own coasts, all those deli- 

 cate animals and marine productions which delight in warmer wa- 

 ters 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, those deli- 

 cate 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 

 immense flow of polar waters known as Humboldt's Current al- 

 most reaches the line before the first sprig of coral is found to 

 grow. 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 havoc which they created among the pilchards there. It 

 may well be questioned if our Atlantic cities and towns do not 

 owe their excellent fish-markets,- as well as our watering-places 

 their refreshing sea-bathing in summer, to this littoral stream of 

 cold water. The temperature of the Mediterranean is 4° or 5° 

 above the ocean temperature of the same latitude, and the fish 

 there are, for the most part, very indifferent. On the other hand, 

 the temperature along our coast is several degrees below that of 

 the ocean, and from Maine to Florida our tables are supplied with 

 the most excellent of fish. The sheep's-head of this cold current, 



