On the Gulf Stream and Currents of the Sea. 165 



quits the sea, his observations go with hira, and are to the world 

 as though they had not been. 



Capt, Manderson, of the royal navy, pubhshed many years ago 

 "An examination into the true course of the Florida Stream," 

 which he ascribed to the Mississippi and the floods of the other 

 rivers emptying into the Gulf. But judging from what we see 

 daily going on in the Mediterranean, the waters from the rivers, 

 especially in summer, when they are at low stages, and when 

 the Gulf Stream runs at the greatest velocity, are not sufficient 

 to supply the water of evaporation. Taking the hypothesis of 

 the English officer for granted, it was asserted by another writer 

 that the velocity of the Gulf Stream might be determined by 

 the freshets in the Mississippi. Capt. Livingston put these the- 

 ories at rest by showing that the volume of water discharged 

 through the Gulf Stream exceeds what is emptied from the Mis- 

 sissippi by more than three thousand times. 



Upon the ruins of this hypothesis, which Capt. Livingston so 

 completely overturned, he advanced the opinion that the velocity 

 of the Gulf Stream " depends on the motion of the sun in the 

 ecliptic, and the influence he has upon the waters of the Atlan- 

 tic." To this day our books on navigation quote this opinion 

 without comment. The most generally received opinion, how- 

 ever, is that the Gulf Stream is caused by the trade winds. 

 This, doubtless, is one of the causes ; but is it of itself adequate 

 to such an effect ? To my mind, the dynamical laws of the 

 ocean, as at present expounded, appear by no means to warrant 

 the conclusion that it is, unless the aid of other agents is also 

 brought to bear. We know of instances in which the water 

 has been accumulated by the force of winds on one side of a 

 lake, or in one end of a canal at the expense of the other ; but 

 they are rare, and the effect of violent, sudden, and particular 

 causes, such as the trades never afford. And this piling up is 

 only known to take place in shallow basins, or against strong 

 currents. 



Supposing the pressure of the waters that are forced into 

 the Caribbean Sea by the trade winds to be the sole cause of 

 the Gulf Stream, that sea and the Mexican Gulf should have 

 a much higher level than the Atlantic. Accordingly the advo- 

 cates of this theory require for its support " a great degree of 

 elevation." Major Rennell likens the stream to "an immense 



