30 THE PHYSICAL GEOGRAPHY OF THE SEA. 



14. Nay, more ; at the very season of the year when the Gulf 

 Stream is rushing in greatest volume through the Straits of Flor- 

 ida, and hastening to the north w^ith the greatest rapidity, there is 

 a cold stream from Baffin's Bay, Labrador, and the coasts of the 

 north, running to the south with equal velocity. Where is the 

 trade-wind that gives the high level to Baffin's Bay, or that even 

 presses upon, or assists to put this current in motion ? The agen- 

 cy of winds in producing currents in the deep sea must be very 

 partial. These two currents meet off the Grand Banks, where 

 the latter is divided. One part of it underruns the Gulf Stream, 

 "as is shown by the icebergs which are carried in a direction tend- 

 ing across its course. The probability is, that this " fork" con- 

 tinues on toward the south, and runs into the Caribbean Sea, for 

 the temperature of the water at a little depth there has been found 

 far below the mean temperature of the earth, and quite as cold as 

 at a corresponding depth off the Arctic shores of Spitzbergen. 



15. "More water can not run from the equator or the pole than 

 to it. If we make the trade-winds cause the former, some other 

 wind must produce the latter ; but these, for the most part, and 

 for great distances, are submarine, and therefore beyond the influ- 

 ence of winds. Hence it should appear that loinds have little to 

 do with the general system of aqueous circulation in the ocean. 



The other " fork" runs between us and the Gulf Stream to the 

 south, as already described. As far as it has been traced, it war- 

 rants the belief that it, too, runs up to seek the so-called higher 

 level of the Mexican Gulf, 



16. The power necessary to overcome the resistance opposed 

 to such a body of water as that of the Gulf Stream, running sev- 

 eral thousand miles without any renewal of impulse from the forces 

 of gravitation or any other known cause, is truly surprising. It 

 so happens that we have an argument for determining, with con- 

 siderable accuracy, the resistance which the waters of this stream 

 meet with in their motion toward the east. Owing to the diurnal 

 rotation, they are carried around with the earth on its axis toward 

 the east with an hourly velocity of one hundred and fifty-seven* 

 miles greater when they enter the Atlantic than when they arrive 

 off the Banks of Newfoundland. In consequence of the difference 



* In this calculation the earth is treated as a perfect .sphere, with a diameter of 

 7925-56 miles. 



