IS THE GULF STREAM A MYTH? 1313 



reasserts, but does not effectually defend, his own 

 theory, and repeats with even more damaging effect 

 his arguments against the rival view. 



Yet one or other theory must at least point to the 

 true view, for the Atlantic is subject to no other agen- 

 cies which can for a moment be held to account for a 

 phenomenon of such magnificence as the Gulf Stream. 



It appears to us 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 over- 

 flow 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. Sub-marine 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 



