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FOUNDERS OF OCEANOGRAPHY 



is, then, very cold water in the deep sea all over the bottom, 

 and this cold water is derived from the polar regions, more 

 especially from the Antarctic by a slow circulation of that 

 cold bottom water along the floor of the oceans towards the 

 equatorial regions. 



There are, however, certain exceptional areas with higher 

 temperatures in deep water. The Sargasso Sea and between 

 the Azores and Madeira and the Canary Isles have a higher 

 mean temperature down to 1,000 fathoms than any other 

 part of the ocean at corresponding depths. Where a barrier 

 to free circulation exists, such as a submarine ridge cutting off 



an enclosed area from the ocean outside, the temperature of 

 the deeper water inside the barrier may be much higher 

 than that at a corresponding depth outside. For example, 

 the Red Sea is cut off from the Indian Ocean by a barrier at 

 about 200 fathoms. Down to that level it shows the same 

 temperatures as those of the ocean, 80° F. at 100 fathoms 

 and 70° F. at 200 fathoms, but at greater depths the Red 

 Sea maintains that temperature down to the bottom at 1,000 

 fathoms, while outside the barrier in the open ocean the tem- 

 perature decreases with the depths to 40° F. at 700 fathoms 

 and about 35° F. at 1,000 fathoms. The same conditions are 

 found in more or less enclosed areas in various parts of the 

 oceans, such as the Sulu Sea, at Celebes, the Azores, and 



