Our Salt'JVater JVorld 327 



The waters of the Gulf Stream are of a deep sap- 

 phire blue, and they show a sharp contrast to the light 

 green of the seas through which they pass in their early 

 course. As this mighty river leaves the Gulf of Mexico, 

 it has a temperature of 84° in summer, which is four 

 degrees higher than obtains in the ocean at the equator. 

 Even in mid-Atlantic, off Nova Scotia, its temperature 

 at no season falls more than 15°; while the northwest- 

 ern coasts of Europe are laved by its warm waters, 

 waters which were heated more than 1,400 miles away 

 under a tropical sun. As a result their winter tempera- 

 tures are raised about 30° above the normal tempera- 

 tures of the latitudes. To its beneficent and genial 

 warmth, England ow^es its humid climate, and Ireland 

 its perennial green. Scotland, graced with verdure 

 throughout eleven months of the year, is in the same 

 latitude as is the bleak and frozen coast of Labrador. 

 And even Lisbon, though in the mild region of the 

 Mediterranean, is not unaffected by the flow of its 

 southward course. Here, too, a parallel may be drawn. 

 In the same latitude Washington is subject to blizzards, 

 and the Potomac sometimes freezes in a single night; 

 Lisbon scarcely knows a frost. 



For the cause or causes of the Gulf Stream, we must 

 turn to the trade winds. These winds prevail along 

 the equatorial belt, and blow steadily all year from east 

 to west. Their strength and impetuosity may vary, but 

 they are always in evidence. They encircle the globe, 

 and are the primary cause of every other great oceanic 

 current. Westward in the Atlantic Ocean, their con- 

 tinuous action sets up a flow of water just north of the 

 equator; and this water, encouraged by these winds, 



