130 TUE OCEAN. [Book V. 



NE. Trade admits ships to take ; in their progress 

 northwards it is often a great help.' ^ And then 

 Major Rennell remarks : 'I am unable to account 

 satisfactorily for the cause of this great derivation 

 from the great trunh stream of equatorial current, 

 unless it be to supply the waste of water, by evapo- 

 ration, within the tract occupied by the ivarm water 

 of the Grulf Stream — in effect its recipient — and the 

 supply of the Mediterranean Sea.' 



As the stream here described runs right across 

 the NE. Trade Wind, it is naturally a stumbling- 

 block in the way of a theory which makes the winds 

 the great prime movers of the oceanic currents ; for, 

 if a stream of this sort run right across the NE. 

 Trade Wind, it is not easy to see how the Trade 

 Winds can be the great prime cause of the Gulf 

 Stream, which does not itself run with the wind. 



Although this stream has not been traced con- 

 tinuously beyond 30° N., we find, in another part of 

 Major Rennell's useful work, further evidences of its 

 existence in a^ com^se coinciding with the theoretical 

 action of vis-inertige which we have described. Re- 

 ferring to a Report on Currents, Major Rennell says : 

 ' An important notice communicated by it is the 

 proof of a counter-current of luarm icater, of 13 to 

 21 miles, running to the westward, and along the 

 south side of the main stream (the Gulf Stream), 

 between the parallels of 35'' and 36°. This is the 

 second example of the same kind. Captain Livingston 

 ' P. 115, ib. 



