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 propelhng power nowhere 
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 the)^ 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. AVhen 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, 915-26 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 axis 
of the earth, about seven hundred and sixty miles the hour at the Grand Banks. 
