§ 89-91. THE GULF STKEAM. 27 



89. Nay, more ; at the very season of the year when the Gull' 

 A bifurcation. Stream is rushing in greatest volume through the 



Straits of Florida, and hastening to the north with the greatest ra- 

 pidity, there is a cold stream from Bafdn's Bay, Labrador, and the 

 coasts of the north, running to the south with equal velocity. 

 Where is the trade-wind that gives the higher level to Baffin's 

 Bay, or that even presses upon, or assists to put this current in 

 motion ? The agency 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 tending across its course. The probability is, that this 

 "fork" flows 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's crust, 

 and quite as cold as at a corresponding depth off the Arctic 

 shores of Spitzbergen. 



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

 Winds exercise but to it. If wc make the trade-winds to cause the 



little influence upon ^ -, n r^ ii I'l 



constant currents. Guli Stream, wc ought to havc some other wind to 

 produce the Polar flow; but these currents, for the most part, 

 and for great distances, are submarine^ and therefore beyond the 

 influence of wnnds. Hence it should appear that icincls have little 

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

 The other " fork" runs between our shores and the Gulf Stream 

 to the south, as already described. As far as it has been traced, 

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

 higher level of the Mexican Gulf. 



91. The power necessary to overcome the resistance opposed 

 Effects of diurnal to such a bodv of watcr as that of the Gulf Stream, 



rotation upon the . , , ^ . ' l^ . 



Gulf Stream. Tunumg scvcral thousand miles without any renew- 



al of impulse from the forces of gravitation or any other known 

 cause, is truly surprising. It so happens that we have an argu- 

 ment for determining, with considerable 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 toivard the east with an hourly velocity 

 of one hundred and fifty-seven* miles greater when they enter 



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

 7925.56 miles. 



