CU.XXL] CURRENTS AND DEPTHS OF MEDITERRANEAN. 



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na ry difference would be impossible but for the existence 

 of a submarine barrier of rock (A, fig. 58) which was found 

 by Admiral Smyth to extend from Cape Trafalgar to Cape 

 Spartel, which are only 22 miles apart. He ascertained 

 that the crest of this ridge could in no part be lower than 

 220 fathoms from the surface; but Captain Spratt informs 

 me, that the French surveyors, in their more recent surveys 

 of 1854 and 1863, have proved that the deepest soundings, 



~~ ers side, do not exceed 167 fathoms. 

 The ridge being from five to seven miles broad, the shal- 

 lowest part of the continuous crest may even now have 

 escaped observation, and it forms a parting wall by which 

 the colder and heavier waters of the Atlantic are prevented 



Mediterranean.* These soundings have 

 dispelled the idea which was once popular, that there was a 

 counter-current at a considerable depth in the Straits of Gib- 

 raltar, by which the water which flows in from the Atlantic 

 was restored to that ocean. The idea of such a counter- 

 current first originated in 

 M. De FAigle, commander of a privateer called the Phcenix 



the following circumstance : 



of Marseilles, gave chase to a Dutch merchant-ship, near 



Ceuta Point, and coming up with her in the middle of the 

 gut, between Tariffa and Tangier, gave her one broadside, 

 which, directly sunk her. A few days after, the sunken ship, 

 with her cargo of brandy and oil, was cast ashore near Tan- 

 ier, which is at least four leagues to the westward of the 

 place where she went down, and to which she must have 

 floated in a direction contrary to the course of the central 

 current, f This fact, however, affords no evidence of an 

 under-current, because the ship, when it approached the 

 coast, would necessarily be within the influence of a lateral 

 current, which running westward twice every twenty-four 

 hours, might have brought back the vessel to Tangier. 



The Black Sea being situated in a higher latitude than the 

 Mediterranean, and being the receptacle of rivers flowing 

 from the north, is much colder, and its loss by conversion into 



* Capt. Spratt, Travels and Kesearches in Crete, 1865 

 t Phil. Trans. 1724. 



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