CURRENTS AND WHALING. 477 



tropical climate must extend thus far, which is the most remote point 

 at which any such stream has been positively known to exist. It 

 may, however, be connected with the strong easterly current that is 

 constantly setting through the Icy Sea, as has been noted in all 

 the voyages in search of a Northwest Passage. At the Aleutian 

 Islands the stream appears to divide, and a branch continues on, at 

 first in a northeast direction, but, gradually changing its course, takes 

 a sweep along the line of the coast of America, and merges in the 

 northeast stream of which we have spoken above. This stream, 

 which passes the Aleutian Islands, is doubtless an equatorial one; its 

 low temperature may be accounted for by the fact of its being mixed 

 with water coming through Behring's Straits by an under-current 

 from a polar region ; this latter being obstructed by the Aleutian 

 Islands, would cause it to be mixed with the surface water, and be 

 carried therewith to the coast of America. It is clear, from the 

 narrow space at Behring's Straits, that no great quantity of water 

 can pass as a submarine current from the Arctic Ocean, to produce 

 any remote effects. 



On our return, in passing from the Hawaiian Group to the Ma- 

 rianes, we experienced a slight current setting to the westward, which 

 may be ascribed to the trade-winds. After passing the latter islands, 

 we found a current setting to the northward, being in all probability 

 connected with the stream that flows along the coast of Japan. This 

 direction prevailed until we reached the straits by which we entered 

 the China seas. 



I need not speak of the currents in the China seas, as they are well 

 known to be influenced by the monsoons, and, therefore, far from 

 constant. Now, as the southwest monsoon has a tendency to increase 

 the Equatorial Stream, and give the waters a direction to the north- 

 east, we may find in this remote region the cause by which the 

 velocity of the southeast current on the northwest coast of America 

 is accelerated at the very season in which such influence might be 

 expected to reach those shores. 



On our track from the China seas towards the Cape of Good Hope, 

 we met with but little current until we approached the east coast of 

 Africa. We had, during this part of our voyage, an opportunity of 

 trying the deep-sea temperature daily, having received several self- 

 registering thermometers, which I had sent for to replace those we had 

 lost. These observations confirmed the impression that this portion of 

 the ocean is but little liable to submarine streams. 



On approaching the east coast of Africa, we found ourselves at first 

 influenced, as mentioned in the Narrative, by the Polar Stream, then, 



