1 82 The Realm of Nature CHAP. 



coast by the branch of the North Equatorial Current, which 

 had passed outside the West Indies and through the 

 Bahamas. The Gulf Stream sweeps the bottom clear of 

 mud not only in the Strait but for a considerable distance 

 northward. As it flows on, it grows wider and shallower ; 

 off Cape Hatteras it curves away from the American coast 

 and coming within the range of the prevailing south- 

 westerly winds, it is carried eastward across the Atlantic, 

 spreading out like a fan and growing cooler as it flows. 

 The Gulf Stream passes to the south of the Grand Banks 

 of Newfoundland with a velocity of about ij miles per 

 hour, and its rate gradually diminishes to about 4 miles a 

 day in the general North Atlantic drift. This drift of 

 comparatively warm water forks into three, diverging toward 

 the coast of Spain, the British Islands, Norway, and the 

 south-eastern coast of Iceland, stranding driftwood on that 

 treeless island. The surface water of t*he tropics is thus 

 being steadily poured into the temperate North Atlantic, 

 where it drives the cold deep water toward the south, and 

 gives rise to the highest temperature at great depths found 

 in any part of the open ocean. The temperature of 40 

 occurs as deep as 900 fathoms off the west of Scotland, 

 and seldom deeper than 300 fathoms in the tropics. This 

 is the source which supplies the south-west wind with 

 heat and moisture to modify the climate of Western 

 Europe. 



245. Polar Currents of the Atlantic. Careful study 

 of the drifting of ice-floes in the Arctic Sea gives some 

 ground for believing that a current sets straight across from 

 near the New Siberian Islands on the coast of Asia toward 

 Arctic North America. Dr. Nansen has resolved to set 

 out in 1892 on an expedition to the North Pole, believing 

 that this current will drift his vessel to the point which so 

 many explorers have hitherto attempted in vain to reach. 

 A cold current, carrying icebergs in summer, when the 

 frozen sea breaks up, flows south from the Arctic Sea 

 between Spitzbergen and Greenland, strengthened by a 

 cold drift from the north coast of Asia. It passes along 

 the north coast of Iceland, where it strands driftwood 



