THE GULF STREAM. 27 



unless it had a ssil bed at the bottom, or was fed with salt springs 

 from below — neither of which is probable — would become a fresh- 

 water basin. 



The above quoted argument of Captain Livingston, however, 

 was held to be conclusive ; and upon the remains of the hypoth- 

 esis which he had so completely overturned, he set up another, 

 which, in turn, has been upset. In it he ascribed the velocity of 

 the Gulf Stream as depending "on the motion of the sun in the 

 ecliptic, and the influence he has on the waters of the Atlantic." 



7. But the opinion that came to be the most generally received 

 and deep-rooted in the mind of seafaring people was the one re- 

 peated by Dr. Franklin, and which held that the Gulf Stream is 

 the escaping of the waters that have been forced into the Carib- 

 bean Sea by the trade-winds, and that it is the pressure of those 

 winds upon the water which forces up into that sea a head, as it 

 were, for this stream. 



We know of instances in which waters have been accumulated 

 on one side of a lake, or in one end of a canal, at the expense of 

 the other. The pressure of the trade-winds may assist to give the 

 Gulf Stream its initial velocity, but are they of themselves ade- 

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

 as at present expounded, appear by no means to warrant the con- 

 clusion that it is, unless the aid of other as-ents also be broug-ht 



' DO 



to bear. 



8. Admiral Smyth, in his valuable memoir on the jMediterra- 

 nean (p. 162), mentions that a continuance in the Sea of Tuscany 

 of '•'gusty gales'^ from the southwest has been known to raise its 

 surface no less than twelve feet above its ordinary level. This, 

 he says, occasions a strong surface drift through the Strait of Bo- 

 nifaccio. But in this we have nothing like the Gulf Stream ; no 

 deep and narrow channel-way ta conduct these waters off like a 

 miniature river even in that sea, but a mere surface flow, such as 

 usually follows the piling up of water in any pond or gulf above 

 the ordinary level. The Bonifaccio current does not flow like a 

 "river in the sea" across the Mediterranean, but it spreads itself 

 out as soon as it passes the Straits, and, like a circle on the water, 

 loses itself by broad spreading as soon as it finds sea room. 



