THE GULP STREA:M. 51 



the Gulf Stream, its progress to the north is arrested. It now 

 turns to the east with the Gulf Stream, and, yielding to the 

 force of the westerly winds of this latitude, is (§ 107) by them 

 sloivhj drifted along : losing temperature by the way, these waters 

 reach the southwardly flow on the east side with their specific 

 gravity so altered that, disregarding the gentle forces of the 

 wind, they heed the voice of the sea, and proceed to unite with 

 this cool flow, and to set south in obedience to those dj-namical 

 laws that derive their force ia the sea from differing specific 

 gravity. 



142. Tlie ressmolance between the currents in the North Atlantic and 

 the North Pacific. — The Thermal Charts of the Xorth Atlantic afford 

 for these views other illustrations which, when compared with 

 the charts of the North Pacific now in the process of construction, 

 will make still more striking the resemblance of the two oceans 

 in the general features of their systems of circulation. *"\Ve see 

 how, in accordance with this principle (§ 132), the currents 

 necessary for the formation of thickly-set sargassos are generally 

 wanting in southern oceans. How closely these two seas of the 

 north resemble each other ; and how, on account of the large 

 openings between the Atlantic and the Frozen Ocean, the flow of 

 A'/arm waters to the north and of cold waters to the south is so 

 much more active in the x\tlantic than it is in the Pacific. 

 Ought it not so to be ? 



143. ^ cushion of cool water protects the bottom of the deep sea from 

 abrasion by its currents. — As a nile, the hottest water of the Gulf 

 Stream is at or near the surface ; and as the deep-sea thermo- 

 meter is sent down, it shows that these waters, though still far 

 warmer than the water on either side at corresponding depths, 

 gradually become less and less warm until the bottom of the 

 current is reached. There is reason to believe that the warm 

 waters of the Gulf Stream are nowhere permitted, in the oceanic 

 economy, to touch the bottom of the sea. There is everj^where 

 a cushion of cool water between them and the solid parts of the 

 earth's crust. This arrangement is suggestive, and strikingly- 

 beautiful. One of the benign offices of the Gulf Stream is to 

 convey heat from the Gulf of Mexico, where otherwise it would 

 become excessive, and to dispense it in regions beyond the 

 Atlantic for the amelioration of the climates of the British 

 Islands and of all Western Europe. Now cold water is one of 

 the best non-conductors of heat, and if the warm water of the 



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