The Mighty Deep 



still it is quite chilly enough in its effects upon 

 the Siberian climate. Here again the cold 

 stream acts as a "wall" to the warm river 

 flowing the other way. 



More reasons than one may help to explain 

 why these two currents slant off to the eastward 

 instead of pouring due north. The shape of the 

 various coastlines has something to do with it ; 

 also the presence of ridges and hollows in the 

 ocean-beds, and the resistance of other contend- 

 ing currents. A river, either on land or in 

 the sea, will always travel where it finds least 

 opposition. 



One main cause, however, is the whirl of our 

 Earth upon its axis. This, which greatly affects 

 the directions of prevailing winds, alters also 

 the lines followed by ocean rivers. 



A current starting from near the equator for 

 the north shares in the rapid rush of the Earth's 

 surface, which at the equator spins eastward 

 at a rate of about one thousand miles each 

 hour. As the volume of water gets farther 

 north, it reaches parts of the Earth which are 

 whirling more slowly, while it has not lost much 

 of its own eastward whirl. A sideways flow is 

 the result, changing the northward into a north- 

 eastward direction. 



54 



