510 CURRENTS AND WHALING. 



forming the surface polar streams, of which we have spoken. Those 

 which come from the great body of ocean in the southern hemisphere 

 are directed upon the projecting points of the continents and great 

 islands, Cape Horn, the Cape of Good Hope, Cape Leeuwin, &c, 

 where, as a general rule, they are divided into two branches. The 

 easternmost of these meet the equatorial streams, of which I have 

 spoken, whose direction they change, modifying or checking their 

 progress towards the poles, and forming what I have termed the 

 nuclei. In the North Atlantic, we have seen that a part at least of 

 the North Polar Stream divides upon Cape Finisterre, passes into the 

 Bay of Biscay, assuming the form of a surface current allied to an 

 eddy, called the Rennell Current, while its main branch pursues its 

 southern course along the coast of Portugal, and finally again becomes 

 wholly submarine. 



On the western side of the North Atlantic, in the higher latitudes, 

 flows the Labrador Stream, a current so powerful that we can hardly 

 ascribe its origin to the return of the tropical waters of the Atlantic 

 alone ; and this, it is thought, may be a portion of the Equatorial 

 Stream of the Pacific, which, after entering the Icy Sea at Behring's 

 Straits, and forming the current which sets eastward, on the northern 

 shores of America, enters the Atlantic through the many passages of 

 that labyrinth of islands and icebergs, and finally returns, to be again 

 heated in the tropical climates of the Atlantic. 



There is unquestionably a greater body of colder water lying at 

 depths in the equatorial regions of the Atlantic than can be accounted 

 for in any other manner than by submarine streams. Separate 

 observations, made in the Vincennes, Porpoise, and Oregon, at dif- 

 ferent places during the return voyage, exhibited the same low 

 temperature at a depth of one hundred fathoms, within a zone lying 

 between the parallel of 3° S. and 3° N. The observed temperatures 

 in the several vessels differed only a degree from each other, and they 

 agreed nearly in the breadth of the first zone. I feel satisfied that the 

 one first met with was connected with the cold submarine stream our 

 deep-sea temperatures showed when near the Cape de Verdes, on the 

 outward voyage. As we crossed the South Atlantic, without noticing 

 any phenomena of this kind, it may be safely asserted that this body 

 of cold water therefore comes from the north. 



But to return to the western branches of the polar streams that set 

 upon the two great promontories of the old and new continents : these 

 are deflected by the land, and in their new direction flow onwards to 



