THE GULF STEBAM. 421 



Gulf Stream may dip below the cold but lighter water of the Arctic 

 Current, as in the Northern regions warmer water has been found at a 

 considerable depth below the colder water on th© surface. 



The same arguments may be used with reference to the bands of warm 

 and cold water (395) met with in the earlier part of its course, where it 

 come in contact with that branch of the Arctic Current, which is con- 

 sidered to have its course to the Southward, off the American coast. 



In 1886, M. J. Thoulet, from observations taken from the French 

 frigate Clorinde, concluded that where the Arctic Current meets the Gulf 

 Stream at right angles, the water of the former, though colder, is a little 

 lighter, so that instead of passing below the warmer water of the Stream, 

 it mixes with it, almost entirely arresting its speed, and from thence to 

 the North-Eastward it is merely a drift. 



(413.) Up to this point we have said nothing about the speculations 

 promulgated respecting the heat-bearing properties of the Gulf Stream ; 

 but, in this book, space will not allow us to enter upon them. Those of 

 Mr. James Croll, however, must be noticed, as they refer to a method of 

 estimating this by the powers of absorption of the sun's rays by the ocean's 

 surface, represented by the dynamic enumeration of foot-pounds. But 

 we would deferentially demur to his calculations. He takes no account 

 of the time it takes for the water to circulate, or of its ascertained depth. 

 He very much exaggerates the known volume of the Stream, and does not 

 refer to the interferences it encounters, the fog banks, nor to the Arctic or 

 Labrador Current. However valuable his suggestions may be, they must 

 be applied in a different way.* 



(414.) Having thus brought the Gulf Stream through its remarkable and 

 well-defined course, which on its Northern margin is not less than 2,200, 

 miles, we arrive at the conclusion, which is here repeated from our former 

 editions, that its farther progress as a distinct current cannot be traced. It 

 merges into the general ocean drifts common to the sea for many hundreds 

 of miles on either side of it. This conclusion is in antagonism with that 

 of many who contend for its extension and evidences up to the shores of 

 N.W. Europe, and into the Arctic basin. But while the facts on which 

 this conclusion is based are not for one moment questioned, yet their con- 

 nexion with the stream, which has thus far been described, is not shown, 

 and the effects claimed for it are so immeasurably greater than the parent 

 source, that they must be inevitably referred to much more powerful 

 causes. These will be briefly discussed in the ensuing section. 



9. NOBTH-EASTEELY SET TO WESTEEN EUEOPE, ETC. 



(415.) The previous pages have brought the Gulf Stream up to the 

 meridian of 50° or 48° W. The Southern portion of the Eastward Current, 

 Southward of lat. 40° N., passing over towards the Azores, with the other 

 drifts, forms the head of the North African Current (265), while the portion 

 North of that parallel ceases as a heat-bearing stream on the same 



• See " Geological Magazine," vol. vi., April, 1869; and "Philosophical Magazine," 

 February, 1870. 



