208 PHYSICAL GEOGKAPHY OF THE SEA : 



from the pen of the great mariner who first traversed it on 

 his way to the discovery of a new world. In a letter written 

 by Columbus in 1498, he relates that in each voyage from 

 Spain to the Indies, he found, about 100 nautical miles to 

 the west of the Azores ; a wonderful change in the aspect of 

 the ocean; so sudden, too, that he uses the word raya to 

 mark the line of boundary. The sea became at once calm 

 and still, scarcely even moved by storms ; but so thickly and 

 strangely matted over wth seaweed, as to suggest instant 

 danger to the ships from running upon shoal banks. Nearly 

 four centuries have elapsed since these phenomena were 

 present to the eager and observant eye of Columbus ; and 

 they still continue as they then were. The same currents 

 sweep round the basin of the Atlantic ; the same stagnant 

 and weedy sea still exists within the circuit of waters thus 

 formed. How changed, meanwhile, the aspect of man's ex- 

 istence on the shores which bound this ocean; and how 

 certain the greater changes during the ages which lie before 

 us ! Many of these changes, and such as may count among 

 the mightiest now in progress, are due to the Atlantic itself, 

 and to that permanence of its physical characters which we 

 have been describing. Not only has it served to the inter- 

 communication of the two hemispheres, but it may almost be 

 said to have created the Western, by the tide of human 

 emigration carried across from the old world to the new. 

 Some of the greatest problems in government and social ex- 

 istence are awaiting their eventual solution in the races thus 

 transplanted ; and especially in the powerful nation, our own 

 immediate offspring, established on the wide and fertile con- 

 tinent of the West. 



We cannot touch upon this vast topic of human transit over 

 the Atlantic, whether for commerce or migration, without re- 

 curring once more to the history of the Gulf-stream. Though 

 in practical navigation its influence must have been often felt, 



