CURRENTS AND WHALING. 491 



to the influence of northeasterly winds. These are known to affect 

 the tides in our bays and harbours, but I am unwilling to admit that 

 these are an adequate cause for the change in position and velocity 

 of so great a body of water. The action is far too trivial to account 

 for such an effect. It is certain, on the other hand, that the Gulf and 

 Labrador Streams both owe their existence to the unequal distribution 

 of temperature on the earth's surface ; there must be a difference in 

 the intensity of the causes that act to produce these effects at different 

 seasons of the year, and it may be inferred that the changes of the 

 seasons act unequally upon the two streams. The force of the por- 

 tion of the Labrador Current, which follows the coast of the United 

 States, will, when superior, carry the Gulf Stream outwards, and 

 when that force diminishes, the Gulf Stream will approach more 

 nearly to the coast, and most nearly when its own relative force is the 

 greatest. Whatever be the ultimate causes of the streams, it would 

 appear that their approximate causes are influenced by temperature — 

 the Gulf Stream being increased in mass and velocity when the tem- 

 perature is highest, and the Labrador Stream when it is lowest; and 

 in conformity, we find it a general impression that the former is 

 broader and more rapid in the summer of our climate than in winter. 

 I must however state, that I have been unable from my own personal 

 observation, either by the thermometer or the set of the vessel, to 

 distinguish this increase of the Gulf Stream in summer. Thus in 

 my passage to England, in August, 1836, from the time we passed 

 to the eastward of George's Bank, in a latitude about a degree to the 

 south of it, we experienced a low temperature in the water, and the 

 vessel was retarded. We were therefore in the Labrador current. 



After the squadron had crossed the Gulf Stream, we experienced 

 little action from current until we reached Madeira, the whole differ- 

 ence between our dead reckoning and the true place of the ship being 

 no more than one hundred and seventy-five miles in twenty-six days. 



Before leaving this part of our subject, it may be as well to refer to 

 facts familiarly known, but which did not come within the scope of 

 our observations. The stream known on our coast by the epithet of 

 Gulf, may often be traced upon the surface, but with diminished 

 velocity, entirely across the Atlantic, throwing at some seasons the 

 seeds and drift of tropical climates upon the British Islands, even as 

 far north as the Shetlands. At other times, when the Gulf Stream 

 ceases to flow, or is overpowered by the great Polar Current, they 

 are carried by the latter to the southeastward, on the coast of Spain 



