CUAP. v.] GENERAL CONCLUSIONS. 267 



water of the Gulf-stream, forced to tlie eastward by its liigli in- 

 itial velocity, and thus accumulated at the head of the Atlantic, 

 whence it has no free egress, becomes "banked down," and the 

 warm stratum abnormally thickened against the coast of West- 

 ern Europe. Some ingenious theories, depending upon changes 

 of density produced by evaporation, and changes of density 

 combined with changes of temperature, have been proposed to 

 account for the great accumulation of water of abnormally high 

 specific gravity, and at an abnormally high temperature in the 

 North Atlantic ; but these do not seem to be satisfactory, and 

 as they can only be supposed to act, at most, as very subordinate 

 auxiliaries to the wind circulation, they sink in importance into 

 the category of questions of detail. 



The branch of the equatorial current deflected to the south- 

 ward of Cape St. Roque passes down as the Brazil Current, 

 parallel with the coast of South America. In its southward 

 extension it finds no barrier corresponding to that which cir- 

 cumscribes and moulds the northern branch. Gradually widen- 

 ing out and becoming less defined, at the same time acquiring 

 a sufficient easterly deflection to keep it out from the coast, it 

 is at length almost merged in the great easterly drift-current 

 which sweeps round the world, occupying a belt 600 to 1000 

 miles broad in the Southern Sea. But while the greater part 

 of the Brazil Current is thus merged, it is not entirely lost ; for 

 at its point of junction with the drift-current of the westerlies 

 all the upper isobathy therms are slightly deflected to tlje south, 

 and opposite the point where this deflection occurs there is 

 comparatively oj)en sea far to the sonthward, and a penetrable 

 notch in the southern pack. Taking advantage of this, Wed- 

 dell, in 1829, and Ross, in 1843, reached the parallels of 14° 14' 

 and Yl° 30' S. respectively, between the meridians of 15° and 

 30° W. The same thing occurs with regard to the Agulhas 

 Current and the East Australian Current ; but the case of the 

 Brazilian Current is a little more complicated than that of the 



