IS THE GULF STREAM A MYTH? 131 



It appears to me, that on a close examination of the 

 Gulf Stream mechanism, the true mainspring of its 

 motion can be recognised. Compelled to reject the 

 theory that the trade- winds generate the equatorial 

 current westward, let us consider whether Herschel's 

 arguments against the * heat theory ' may not suggest a 

 hint for our guidance. He points out that an overflow 

 from the equator polewards would result in an eastward, 

 and not in a westward, current. This is true. It is 

 equally true that a flow of water towards the equator 

 would result in a westward current. But no such flow 

 is observed. Is it possible that there may be such a 

 flow, but that it takes place in a hidden manner ? 

 Clearly there may be. Submarine currents towards 

 the equator would have precisely the kind of motion we 

 require, and if any cause drew them to the surface near 

 the equator, they would account in full for the great 

 equatorial westward current. 



At this point we begin to see that an important 

 circumstance has been lost sight of in dealing with the 

 heat theory. The action of the sun on the surface- 

 water of the equatorial Atlantic has only been consi- 

 dered with reference to its warming effects. But we 

 must not forget that this action has drying effects also. 

 It evaporates enormous quantities of water, and we 

 have to inquire whence the water comes by which the 

 sea-level is maintained. A surface flow from the sub- 

 tropical seas would suffice for this purpose, but no such 

 flow is observed. Whence, then, can the water come 

 but from below ? Thus we recognise the fact that a 



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