

The Sea and Its Work 



Spain and Northern Africa. The cause of the 

 Gulf Stream is undoubtedly to be sought in the 

 so-called "Trade Winds," which, constantly 

 blowing more or less from the north-eastward, 

 give a westerly impulse to the inter-tropical 

 surface waters of the Atlantic, and thus create 

 the current, which sets into the gulf of Mexico. 

 But, whether the stream, after it leaves the coasts 

 of the United States, retains sufficient impetus 

 to carry it to our shores; or whether, as some be- 

 lieve, the true Gulf Stream is lost in the middle 

 of the Atlantic, and any warm currents felt on 

 our own coasts are due to the predominant south- 

 westerly winds of the temperate part of the 

 Atlantic, is as yet uncertain. 



The general course of the Gulf Stream is 

 shown in Fig. 44. Where the water issues from 

 the Gulf of Mexico, through the Florida Narrows, 

 it has a temperature of upwards of 80 Fahr. and 

 moves at the rate of between four and five miles 

 an hour. In passing across the Atlantic the cur- 

 rent widens and its speed is slackened, but it 

 cools with extreme slowness, so that it carries 

 along a considerable store of heat. The stream 

 forms, in fact, a sharply defined river of warm 

 water flowing over the colder water of the ocean. 



When we bear in mind the effect of heat in 

 altering the bulk of bodies, it will be understood 

 that a body of warm water, like that of the 

 Gulf Stream, can easily float upon water which 

 is colder and therefore denser. When a mass of 

 water is unequally heated, by raising its tem- 

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