422 OBSEEVA.TIONS ON THE CUERENTS. 



meridian. Its further progress is manifestly entirely cut off by the very 

 much deeper Arctic Current ; and this is the case throughout the year. 



But it is contended by Dr. Petermann, that as the ocean becomes sud- 

 denly warmer to the Eastward of the meridian of 48°, and this, too, for 

 an extent of not less than 300 or 400 miles in a N.N.W. direction in July, 

 or N.N.E. direction in January, as shown by the direction of the isotherms, 

 this warmer water must be the Gulf Stream.* Undoubtedly, looking only 

 to the direction of the isotherms, there would seem to be grounds for this 

 assertion ; but the positive fact that the Polar Stream entirely intersects 

 it, and that there is not the slightest evidence of amj Northerly set to the 

 East of the Great Bank (on the surface at least) precludes such a suppo- 

 sition. The Eastward course of the surface waters is continued alike over 

 the colder as over the warmer areas ; and as the surface temperature we 

 are discussing must be dependent in some degree on surface motion, there 

 must be some other great agent at work to produce this effect. How this 

 operates is not clear; and, like many other mysteries of the Ocean, it 

 awaits an explanation. It is certainly not caused by surface current. 



Looking at the general arrangement of the isotherms, it would seem as 

 if the waters of the Ocean South of the parallel of 45° or 60° N. latitude, 

 and Eastward of the 40° meridian, were at their normal temperature, and 

 that it was the effect of the Polar Stream, and the arrangement of the land 

 on the Western side of the Ocean, that broke up the symmetry, by forcing 

 the warmer waters several degrees of latitude Southward of the position 

 they would occupy but for this combination of causes. 



The rate of the drift is from 6 or 10 miles to 20 or 24 miles per day; and 

 as far as 50° N. it seems generally to flow due East towards the French 

 and Portuguese coasts, and thus forms the hesid of the occasional Rennell's 

 Current. But, singular to say, observations are not abundant hereabout, 

 and the true rate can only be given approximately ; it is of no great power, 

 and has but little effect on a vessel's course. Beyond the doubt, whether 

 the water thus far can be considered as the Gulf Stream, there is no con- 

 troversy as to this part of the Ocean circulation. 



(416.) It is to the N.E. of this that there is a difference of opinion. It 

 was generally believed, in former times, that the climate of the Western 

 portion of the British Isles, that of Norway, Iceland, and a large area 

 around the Northern part of Europe, was dependent on the Gulf Stream, 

 which flowed continuously throughout as a heat-bearing current ; but this 

 cannot now be maintained, since we have been made intimately acquainted 

 with the dimensions and character of the Stream in its greatest strength. 



(417.) Bottles. — The observations for its Velocity and Direction are not 

 very numerous ; and, therefore, we have recourse to the drift of floating 

 bottles, about which much controversy took place, at the time they were 

 collectively brought forward in the " Nautical Magazine," in 1853. As 

 they tell a singularly consistent tale, which is entirely confirmed by similar 



• «« It is by no means annihilated (by the Polar Stream) ; on the contrarj', it sallies 

 forth intact from the conflict." " Again : " The Gulf Stream is not disturbed to any 

 degree, either in its direction or in its temperature, until a very short distance East of 

 Newfoundland, when it bends sharply round to the North," — Mittheilungen, 1870, pnge 

 220. Knorr, pages 43, 44. 



