68 THE PROBLEMS OF THE DEEP SEA n 



Again, if tlie Gibraltar indraught is the effect of 

 evaporation, why does it go on in Avinter as well 

 as in summer ? 



All these are questions more easily asked than 

 answered ; but they must be answered before we 

 can accept the Gibraltar stream as an example 

 of a current produced by indraught with any 

 comfort. 



The Mediterranean is not included in the 

 Challengers route, but she will visit one of the 

 most promising and little explored of hydro- 

 graphical regions — the North Pacific, between 

 Pol3rQesia and the Asiatic and American shores ; 

 and doubtless the store of observations upon the 

 currents of this region, which she will accumulate, 

 when compared with what we know of the North 

 Atlantic, will throw a powerful light upon the 

 present obscurity of the Gulf-stream problera. 



