THE GULF STREAM. 35 



ematical demonstration, that to overcome the resistance opposed 

 in consequence of its velocity would require a force at least suffi- 

 cient to drive, at the rate of three miles the hour, ninety thousand 

 millions of tons up an inclined plane having an ascent of three 

 inches to the mile.* Yet heat, the very principle from which one 

 of these agents is derived, is admitted to be one of the chief causes 

 of those winds which 'are said to be the sole cause of this current. 



26. The chemical properties, or, if the expression be admissible, 

 the galvanic properties of the Gulf Stream waters, as they come 

 from their fountains, are different, or, rather, more intense than 

 they are in sea water generally. If so, they may have a peculiar 

 molecular arrangement or viscosity that resists the admixture of 

 other sea waters differing in temperature and saltness. It is a 

 well known fact, that waters of different temperatures, when put 

 in the same vessel, do not readily mix of themselves, but require 

 the process of agitation. Nor do large volumes of water in mo- 

 tion readily admit of the admixture of water at rest. 



In 1843 the Secretary of the Navy took measures for procur- 

 ing a series of observations and experiments with regard to the 

 corrosive effects of sea water upon the copper sheathing of ships. 

 With patience, care, and labor, these researches were carried on 

 for a period of ten years ; and it is said the fact has been estab- 

 lished, that the copper on the bottom of ships cruising in the Ca- 

 ribbean Sea and Gulf of Mexico suffers more from the action of 

 sea water upon it than does the copper of ships cruising in any 

 other part of the ocean. In other words, the salts of these waters 

 create the most powerful galvanic battery that is found in the 

 ocean. 



27. Now it may be supposed — other things being equal — that 

 the strength of this galvanic battery in the sea depends in some 

 measure upon the proportion of salts that the sea waters hold in 

 solution, and also upon temperature. 



28. If, therefore, in the absence of better information, this sug- 

 gestion be taken as a probability as to the origin of these galvanic 

 properties, we may go a step farther, and draw the inference that 

 the waters of the Gulf Stream, as they rush out in such volume 



* Supposing there be no resistance from friction. 



c 



