124 OUR HERITAGE THE SEA 



its progress being accelerated as its channel is nar- 

 rowed, not now by the cold banks of water on either 

 side of it, but by the barrier of Cuba on the north and 

 the mainland of Central America, the peninsula of 

 Yucatan on the south. Presently it meets with an 

 impassable barrier, the continent of America, staying 

 its further westward course, and, driven by the irre- 

 sistible thrust of the great body of water behind it, 

 takes the only road possible, that is, it turns first 

 northward, then eastward, returning along the northern 

 shores of the Gulf with ever-increasing speed. And 

 now the Gulf Stream is in being. Out of the narrow 

 Florida Channel pour the superheated waters, struggling 

 to make their escape from the pressure behind. In 

 the Bahama Channel, cramped into the breadth of less 

 than fifty miles, they sometimes attain a sjJeed of one 

 hundred and ten miles per day, gaining their impetus 

 for their long journey across the Atlantic. 



It is time to drop the plural and speak of the 

 Gulf Stream as an entity, and one that has probably 

 had a greater influence upon the history of the world 

 than that of any other of the physical phenomena 

 with which we are acquainted. Immediately upon 

 emerging into the open Atlantic it spreads out and 

 slackens its speed. Practically following the contour 

 of the North American coast, but kept well off the 

 shore by the cold stream pouring southward from 

 the Arctic, it flows on ever northward and eastward 

 withal, until, happily for us, it is met by the full 

 force of the icy current flowing south from Davis 

 Straits, and deflected so that its main body points 

 almost directly to these favoured islands. It is a 

 veritable river in the sea, a river of warm water whose 



