MEETING OF HOT AND COLD CITERENTS. 67 



gradually approaches nearer the surface. At Cape Hatteras the 

 depth of the current is about 120 fathoms, and its speed does 

 not exceed three miles per hour ; but it is twice as wide when 

 it emerges from the strait of Bemini^ and spreads over a space 

 of about 78 miles. The thickness of this powerful stream of warm 

 water is constantly diminishing, and when it has crossed the 

 Atlantic it is only a superficial sheet. But even then, it covers an, 

 immense extent, reaching from the Azores to Iceland and Spitz- 

 bergen. 



The soundings taken since 1845 by the Officers of the Coast Survey 

 of North America, prove that the Gulf-stream flows along the coast of 

 the United States at some distance from the land. The slight inclin- 

 ation of the low lands of Georgia and Carolina is continued under 

 water till the lead reaches a depth of about 50 fathoms. The 

 bottom then sinks rapidly, and forms a long valley parallel to 

 the shore of the United States and the chalky walls of the Appa- 

 lachians ; it is in this valley, hollowed to the east of the subma- 

 rine basement of America, that the waters of the Gulf-stream flow. 

 Owing to the rotatory motion of the globe, and probably also to the 

 general direction of the coasts, the current follows a constant direction 

 to the north-east, and does not touch any of the advanced points of 

 the continent. Ofl" New York and Cape Cod it deviates more and 

 more to the east, and ceasing to follow at a distance the American 

 coast- line, rolls across the open Atlantic towards the shores of western 

 Europe. Thus, as Maury says, if an enormous cannon had force 

 enough to send a bullet from the strait of the Bahamas to the North 

 Pole, the projectile would follow almost exactly the curve of the Gulf- 

 stream ; and gradually deviating on its way, would reach Europe 

 from the west. 



Between the 43rd and 47th degrees of north latitude, in the neigh- 

 bourhood of the bank of Newfoundland, the Gulf-stream, coming from 

 the south-west, meets on the surface of the sea the polar current 

 discovered by Cabot in the year 1497. The line of demarcation be- 

 tween these two oceanic rivers is never absolutely constant, but varies 

 with the seasons. In winter, that is to say from September to March, 

 the cold current drives the Gulf-stream towards the south ; for during 

 this season all the circulatory system of the Atlantic, winds, rains, 

 and currents, approach more nearly the southern hemisphere, above 

 which the sun travels. In summer, that is to say from March to 

 September, the Gulf- stream in its turn resumes its preponderance, 

 and forces back the line of its conflict with the polar current more 



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