The Mighty Deep 



could be divided into one hundred equal portions, 

 ninety-two of those portions would be found 

 covered by water at a temperature of less than 

 40 ; and only eight of them would lie under 

 warm water. The vast mass of the ocean is 

 cold, with a thin warm layer over certain 

 districts. 



Little doubt can there be that this under-layer 

 is largely fed from polar regions. 



We know that cold ocean-rivers pour from 

 north-polar regions to the south, both in the 

 Atlantic and in the Pacific. A general creeping 

 under-flow of icy waters towards the equator 

 evidently balances the general surface drift of 

 warm waters towards the poles. Since cold 

 water is heavier than warm, it would naturally 

 find its way to lower depths, leaving the warm 

 light liquid to float on the top. 



In the Mediterranean Sea a marked contrast 

 is found. There no ice-cold layer is spread over 

 the bottom ; and the water in its uttermost depths 

 over two miles and a quarter does not sink 

 below the temperature of 54 F. The heat of 

 the sun in South Europe can hardly be compared 

 with the heat of the sun over the Indian Ocean. 

 Yet the latter has water far below the surface 

 down to at least 35. 



48 



