166 On the Gulf Stream and Currents of the Sea. 



river descending from a higher level into a plain." Now, we 

 know very nearly the average surface breadth and velocity of the 

 Gulf Stream in the Florida Pass. We also know with a like 

 degree of approximation the velocity and breadth of the same 

 waters off Cape Hatteras. Their breadth here is about seventy 

 five miles against thirty two in the Narrows of the straits, and 

 their mean velocity is three knots off Hatteras against four in 

 the Narrows. This being the case, it is easy to show that the 

 depth of the Gulf Stream off Hatteras is not so great as it is in 

 the Narrows of Bernini by nearly one half; and that consequently, 

 instead of descending, its bed represents the surface of an inclin- 

 ed plane from the north, up which the lower depths of the stream 

 must ascend. If we assume its depth off Bernini to be two hun- 

 dred fathoms, (which are thought within limits,) the above rates 

 of breadth and velocity will give one hundred and fourteen fath- 

 oms for its depth off Hatteras. The waters, therefore, which in 

 the straits are below the level of the Hatteras depth, so far from 

 descending, are actually forced up an inclined plane, whose sub- 

 marine ascent is not less than ten inches to the mile. 



The Niagara is *' an immense river descending into a plain ;" 

 but, instead of preserving its character in Lake Ontario as a dis- 

 tinct and well defined stream for several hundred miles, it spreads 

 itself out, and its waters are immediately lost in those of the 

 lake. Why should not the Gulf Stream do the same ? It grad- 

 ually enlarges itself, it is true ; but instead of mingling with the 

 ocean by broad spreading as the "immense rivers" descending 

 into the northern lakes do, its waters, like a stream of oil in the 

 ocean, preserve their distinctive character for more than three 

 thousand miles. Moreover, whilst the Gulf Stream is running 

 to the north from its supposed elevated level at the south, there is 

 a cold current coming down from the north with great velocity. 

 Meeting the warm waters of the Gulf midway in the ocean, it 

 divides and runs by the side of them right back into those very 

 reservoirs at the south, to which" theory gives an elevation suffi- 

 cient to send out entirely across the Atlantic a jet of warm water 

 said to be more than three thousand times greater than the Mis- 

 sissippi River ! 



Now this current from Baffin's Bay has not only no trade winds 

 to give it a head, but for a great part of the way it is below the 

 surface and far beyond the propelling reach of any wind. And 



