6 SEA-BIRDS 



and Trinidad to flow with scarce-abated force into the Caribbean, 

 mainly through the channel between Trinidad and Grenada in the 

 Windward Islands. 



Through the Caribbean the current flows from east to west, 

 turning northerly and entering the Gulf of Mexico through the fairly 

 narrow channel between Yucatan and Cuba. It is no doubt aided 

 here by the climate, for this part of the world is very hot, and not 

 excessively wet, and there is much evaporation of the waters of the 

 Caribbean and the Gulf of Mexico, which has to be replaced. The 

 current finally comes up against the coast of Louisiana and Texas 

 and proceeds to mill right-handed, escaping finally through the narrow 

 gap between Florida and Cuba, into the Bahama Seas. 



Here the Gulf Stream is formed, not only by the waters escaping 

 from the Gulf of Mexico but by more northerly elements of the equa- 

 torial current which impinge upon the outer shores of the West Indies 

 and are deflected northwards. This north equatorial current flows 

 across the ocean from the Cape Verde Islands and the joint product 

 swings quickly east again, narrowing in width but probably gaining 

 in velocity, to sweep past the tail of the Great Bank of Newfoundland 

 and thence to carry on as what is now called the West Wind Drift 

 (because of its associated air currents) . The most direct continuation 

 of this drift flows northwards and eastwards past the west coast of 

 Ireland (giving off* a branch towards Iceland), between Rockall and 

 the Hebrides, through the channel between Shetland and Faeroe, 

 north-eastward up the coast of Norway, whence elements strike east 

 into the Barents Sea and north to reach Spitsbergen. It is because of 

 this warm drift that, of all lands reaching latitude 80°, Spitsbergen 

 has been the most accessible. If it was not for the Gulf Stream, many 

 Oxford expeditions could never have explored there in the Long 

 Vacation and got back in time for the Michaelmas Term. 



So far we have described the simplest and best-known currents 

 of the North Atlantic. The fate of the waters in their return circulation 

 is more complex. Much of the return circulation is below the surface, 

 for cool water is denser than warm water. In the lower latitudes of 

 the North Atlantic, between the westward-flowing north equatorial 

 current, and the eastward-flowing Gulf Stream and drift, there is an 

 area of clock-wise milling. The centre of this area is the part of least 

 water-movement, and bears some resemblance to an oceanic desert. 

 This is the Sargasso Sea, usually windless, too, with masses of the 

 floating Sargasso weed, which has berry-like air vessels, and is used 



