42 THE PHYSICAL GEOGRAPHY OF THE SEA. 



Frozen Ocean (Plate IX.). Accordingly, they take (§ 47), in obe- 

 dience to this physical law, the most direct course by which na- 

 ture will permit them to reach their destination. And this course, 

 as already remarked (^ 49), is nearly that of the great circle, and 

 exactly that of the supposed cannon ball. 



51. Many philosophers have expressed the opinion — indeed, the 

 belief is common among mariners (§ 46) — that the coasts of the 

 United States and the Shoals of Nantucket turn the Gulf Stream 

 toward the east ; but if the view I have been endeavoring to make 

 clear be correct — and I think it is — it appears that the course of 

 the Gulf Stream is fixed and prescribed by exactly the same laws 

 that require the planets to revolve in orbits, the planes of which 

 shall pass through the centre of the sun ; and that, were the Nan- 

 tucket Shoals not in existence, the course of the Gulf Stream, in 

 the main, would be exactly as it is and where it is. The Gulf 

 Stream is bound over to the North Sea and Bay of Biscay partly 

 for the reason, perhaps, that the waters there are lighter than 

 those of the Mexican Gulf (§ 36);* and if the Shoals of Nantuck- 

 et were not in existence, it could not pursue a more direct route. 

 The Grand Banks, however, are encroaching, and cold currents 

 from the north come down upon it : they may, and probably do, 

 assist now and then to turn it aside. 



52. Now if this explanation as to the course of the Gulf Stream 

 and its eastward tendency hold good, a current setting from the 

 north toward the south should have a westward tendency. It 

 should also move in a great circle (§ 49), or rather in the circle of 

 trajection, calling thus the circle traced upon the earth which 

 would be described by a trajectile moving through the air without 

 resistance and for a great distance. Accordingly, and in obedi- 

 ence to the propelling powers, derived from the rate at which dif- 

 ferent parallels are whirled around in diurnal motion, we find the 

 current from the north, which meets the Gulf Stream on the Grand 

 Banks (Plate IX.), taking a souihivestiva7'dly direction, as already 

 described (^ 45). It runs down to the tropics by the side of the 

 Gulf Stream, and stretches as far to the west as our own shores 

 will allow. Yet, in the face of these facts, and in spite of this 

 force, both Major Rennell and M. Arago make the coasts of the 



* The waters of the Atlantic generally contain 5^ per cent, more of saline matter 

 than those of the English Channel. — M. Bouillo7i la Grange, 



