472 CURRENTS AND WHALING. 



was of the same description as we afterwards experienced in other 

 similar cases, namely, an increase. We thus have a fact to aid in 

 proving that the opinion generally entertained, that on coming into 

 soundings, or near islands, the temperature always falls, is not correct. 

 I am of opinion that this diminution only takes place where polar 

 streams prevail, and particularly if they be submarine. The obstruc- 

 tion throws their waters upward, and mingles them with those at the 

 surface, which causes the low temperature. It would therefore seem 

 as if the existence of polar currents may be shown by a fall of tem- 

 perature on coming within soundings, and that when this does not 

 occur, it may be assumed as certain, that no polar current prevails in 

 the neighbourhood. 



Between the Society Islands and the Samoan Group, it may be said 

 that there are no currents. The distance is about two thousand miles, 

 and our passage occupied fourteen days, during which time the whole 

 amount of drift was forty-three miles in a direction N. 9° W. 



On approaching the latter group, the temperature of the water rose 

 a few degrees, indicating, according to the view I have already taken, 

 that there was no submarine cold current. 



Around the Samoan Group a current appeared to revolve; for on the 

 southern side it set continually eastward, while on the northern side it 

 set to the west. This current is weakest near the shores, and is not 

 fully developed until at some distance from the islands. This pheno- 

 menon has little connexion with the tides, and does not appear to be 

 connected with the general system : at least I have been unable to 

 account for it on general principles. A knowledge of its existence is 

 however of importance to the navigator, as advantage may be taken 

 of the easterly direction of that part to the south of the islands, in beat- 

 ing to windward. 



On leaving the Samoan Islands for Sydney, and passing to the west- 

 ward of the Feejee Group, a current was found setting to the southwest, 

 and this prevails beyond the latter islands. 



As we approached Lord Howe's Island and Bell's Pyramid, we met 

 a current setting north, in which direction our drift on the passage to 

 Sydney was one hundred and twenty miles. In the neighbourhood of 

 the first-named island, the temperature of the water fell to 66°. After 

 this, however, and before making the coast of New South Wales, the 

 temperature of the water rose to 73°, and we experienced the effects of 

 a stream that sets to the southward parallel to the coast of New 

 Holland. This current, like the Gulf Stream, is variable in breadth 

 and strength, and at certain seasons of the year runs with great 

 rapidity. The occurrence of this stream renders it advisable that 



