THE IMPENETRABLE SEA 



imagination, for seventy-five million tons of water are 

 transported past any given spot in the vast circular 

 stream in every second of time. 



The Gulf Stream is a section of the largest ''water 

 wheel" in the world. As the earth turns on its axis at a 

 thousand miles an hour, the Ocean River, moving within 

 the vast envelope of water which clings to the spinning 

 earth, is also turning, but far more sluggishly, for the 

 average rate of its revolution is three or four miles an 

 hour only. Yet it spins, day after day and century after 

 century : a mighty river of water carrying thousands of 

 ships on its surface and countless myriads of living 

 creatures within its swirling depths. 



Complicated by the entrance and exit of innumerable 

 currents and counter-currents, eddies, tributaries and 

 other forms of moving water, the great Wheel River of 

 the North Atlantic, under the lash of the trades, runs 

 towards the American continent in a westerly direction, 

 and might girdle the globe itself if its flow were not 

 checked and channelled by the interposed land-masses 

 and sent spinning clockwise by the earth's rotary 

 motion. 



There are surfaces below the sea's actual surface. These 

 are formed by layers of water of different densities in the 

 ocean deeps — the upper area of each layer being a sur- 

 face in contact with the lower area of the layer above it. 

 These concealed surfaces are — like the more generally 

 known surface of the ocean itself — traversed by waves. 

 The waves are caused by rhythmic undulations which pass 

 over the concealed surfaces, and they dwarf the greatest 

 waves ever recorded on the actual surface of the sea 

 above them. Exhaustive temperature measurements have 

 shown that the ocean's concealed surfaces are rising and 

 falling incessantly as waves which often reach heights of 

 as much as 300 feet. The cause of these submarine 

 waves, far down in the deeps, is quite unknown to us, 

 but we do know that their movements affect the com- 



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