THE MOVING WATERS 



cisco, and much of Tokyo, where there is Httle or no land 

 forty feet above sea-level. 



The sediment brought down into the sea by rivers, 

 together with the water continually delivered into it by 

 melting ice-caps (in fact everything received by the sea) 

 is forever churned and widely distributed by the currents 

 of the ocean. Little is known of the forces which originate 

 the deep-water movements. The layering of the under- 

 water surfaces, and the directions in which their water 

 masses travel may be determined by heating, cooling, 

 evaporation and rainfall. There is much uncertainty 

 about the speeds of the deep currents — some authorities 

 give them speeds a hundred times as great as those of 

 other authorities. Human knowledge is built up, like a 

 coral reef, laboriously and slowly. 



Countless millions of tiny creatures contribute their 

 individually insignificant efforts to the building of a reef. 

 They labour unseen and their task might, in its earliest 

 stages, seem impossible. Yet their co-operative eflforts 

 bring the reef to the surface at last, and far above it. 

 So the labours of innumerable humans (many of them 

 fated to live and die unknown to the world) result in an 

 accumulation of knowledge which at long last emerges 

 into the light. 



There are many similarities between ocean and at- 

 mospheric conditions, and of these one of the most sig- 

 nificant is the existence of rotatory movements in both. 

 There are wheels within wheels in the atmosphere and 

 wheels within wheels in the sea. 



The currents of the Atlantic may be roughly simplified 

 into two circling streams : one turning clockwise in the 

 North Atlantic and the other spinning anti-clockwise in 

 the South Adantic. The Gulf Stream is part of the North 

 Atlantic ''whirlpool", a system of currents called by the 

 ancients "Oceanus" or the "Ocean River". The word 

 "river", appHed to the North Atlantic stream is a com- 

 monplace one concealing a fact which challenges the 



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