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On the Currents of the Atlantic, and the Existence of thi 

 North- West Passage. 



Lieutenant Maury says, that in studying the system of 

 oceanic circulation he had found it necessary to set out with 

 a very obvious and simple principle — viz., that from what- 

 ever part of the ocean a current was found to run, to the 

 same part a current of equal volume was obliged to return. 

 Upon this principle was established the whole system of 

 currents and counter-currents. It is not necessary to asso- 

 ciate with oceanic currents the idea that they must of 

 necessity, as on land, run from a higher to a lower level. 

 So far from this being the case, some currents of the sea 

 actually run up hill, while others run on a level. The Gulf 

 Stream was of the first class. The bottom of this stream he 

 had shewn some years since to be an inclined plane, running 

 upwards. If the Gulf Stream was two hundred fathoms 

 deep in the Florida Pass, and but one hundred fathoms off 

 Hatteras, it is evident that the bottom would be uplifted 100 

 fathoms within that distance, and that, while the bottom of 

 the Gulf Stream was up hill, the top preserved the water-level, 

 or nearly so. The currents which run from the Atlantic into 

 the Mediterranean, and from the Indian Ocean into the Red 

 Sea, were the reverse of this, that the bottom of the current 

 was a water-level, and the top an inclined plane running down 

 hill. The Red Sea, for example, lies for the most part in a 

 rainless and riverless district. It may be compared to a long 

 narrow trough. It is about one thousand miles long, extend- 

 ing nearly north and south, from latitude 12° or 13°, to the 

 parallel of 30° N. The evaporation from its surface is im- 

 mense, and may be safely assumed to equal a rate of two- 

 tenths of an inch per day. Now, if we suppose the current 

 which runs into this sea to average from mouth to head 

 twenty miles a day, it would take the water fifty days to 

 reach the head of it. If it lose two-tenths of an inch from 

 its surface daily by evaporation, by the time it reached the 

 isthmus of Suez it would have lost ten inches from its sur- 

 face. Thus the waters of the Red Sea ought to be lower 



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