THE GULF STREAM. 31 



of latitude between the parallels of these two places, their rate of 

 motion around the axis of the earth is reduced from nine hundred 

 and fifteen* to seven hundred and fifty-eight miles the hour. 



17. Therefore this immense volume of water, in passing from 

 the Bahamas to the Grand Banks, meets with an opposing force 

 in the shape of resistance, sufficient, in the aggregate, to retard it 

 two miles and a half the minute, and this only in its eastwardly 

 rate. If this resistance be calculated according to received laws, 

 it will be found equal to several atmospheres. And by analogy, 

 how inadequate must the pressure of the gentle trade-winds be to 

 such resistance, and to the effect assigned them ? If, therefore, 

 in the proposed inquiry, we search for a propelling power novvhere 

 but in the higher level of the Gulf, we must admit, in the head of 

 water there, the existence of a force capable of putting in motion, 

 and of driving over a plain at the rate of four miles the hour, all 

 the waters, as fast as they can be brought down by three thou- 

 sand such streams as the Mississippi River — a power, at least, suf- 

 ficient to overcome the resistance required to reduce from two 

 miles and a half to a few feet per minute the velocity of a stream 

 that keeps in perpetual motion one fourth of all the waters in the 

 Atlantic Ocean. 



18. The facts, from observation on this interesting subject, af- 

 ford us at best but a mere glimmer of light, by no means sufficient 

 to make any mind clear as to a higher level of the Gulf, or as to 

 the sufficiency of any other of the causes assigned for this wonder- 

 ful stream. If it be necessary to resort to a higher level in the 

 Gulf to account for the velocity off Hatteras, I can not perceive 

 why we should not, with like reasoning, resort to a higher level 

 off Hatteras also to account for the velocity off the Grand Banks, 

 and thus make the Gulf Stream, throughout its circuit, a descend- 

 ing current, and, by the reductio ad ahsurdum^ show that the trade- 

 winds are not adequate to the effect ascribed. 



19. When facts are wanting, it often happens that hypothesis 

 will serve, in their stead, all the purposes of illustration. Let us, 

 therefore, suppose a globe of the earth's size', having a solid nu- 

 cleus, and covered all over with water two hundred fathoms deep ; 



* Or, 91526 to 758-60. On the latter parallel the current has an east set of about 

 one and a half miles the hour, making the true velocity to the east, and on the axi« 

 of the earth, about seven hundred and sixty miles the hour at the Grand Banks. 



