7^ TRAVELS IN BRAZIL. 



considerable, falling into the Mediterranean, and 

 that of the Black Sea, entering it from the east ; 

 this pressure can become sensible only at the 

 single, proportionably narrow, issue of the Mediter- 

 ranean, where it easily overcomes^ the counter- 

 pressure of the ocean, the force of which is broken 

 by the coast of the two continents, by which it is 

 bounded. Lastly, in considering the causes of this 

 motion of the waters, we must bear in mind the 

 possibility of a dam, which when the two seas 

 formerly broke through the isthmus which se- 

 parated them, still remained, and even now causes 

 certain directions in the course of the water. The 

 inconsiderable lateral currents, on the surface of 

 the strait, towards the west, which Tofino, and 

 others before him, have remarked, are perhaps to 

 be considered as secondary effects of the main cur- 

 rent, such as are observed on the banks of large 

 rivers, and as they are chiefly observed at new and 

 full moon, partly as caused by that planet. 



It is a general opinion of the Spanish fishermen, 

 that the strait grows gradually wider, and this per- 

 fectly coincides with the historical accounts of the 

 breadth of the strait.* This enlargement of the 



* The earliest statement of Skylax of Caryanda makes the 

 breadth of the strait equal to that of the Thracian Bosphorus, 

 that is only a quarter of a geographical mile. The accounts of 

 the breadth make it greater as they approach nearer to our 

 times. Thus, later than the time of Skylax, it is stated at three- 

 fifths of a geographical mile ; still later, at one geographical 



