204 PHYSICAL GEOGRAPHY OF THE SEA : 



according to Livingstone's careful estimate, being about the 

 proportion of the gulf to the river stream. Another hypo- 

 thesis, again, to which the names of Dr. Franklin and Major 

 Eennell give some sanction, assigns a higher level a 

 heaping up, as it were, of the waters in the Grulf of Mexico, 

 in effect of those forced into this great basin by the trade- 

 winds of the Atlantic thereby giving to the Grulf-stream the 

 character of an immense river descending from this higher 

 level to a lower one. Captain Maury suggests, we think, 

 valid objections to this hypothesis; and even contends, from 

 the relative depth of the stream in the Narrows of Bernini 

 and of Hatteras, that instead of descending, its bed represents 

 the surface of an inclined plane with a descent from north to 

 south, up which plane the lower depths of the stream must 

 ascend. We are bound to say that he does not replace, by 

 any complete theory, the opinions which he thus annuls. 

 Nor is it, in truth, easy to frame one which shall meet all 

 the conditions required, seeing the present imperfect state 

 of our knowledge of the mutual influence and action of the 

 mighty agents concerned in such phenomena the ocean, 

 the atmosphere, the rotation of the earth on its axis, the 

 change of seasons, the tides, the heat and cold of different 

 regions, and possibly other influences, of the obscurity of 

 which we have just spoken. All who are familiar with the 

 science of Hydrodynamics and the theory of waves, know 

 that these subjects involve problems requiring for their 

 solution the highest mathematical power, based upon the 

 most exact experiment and observation; questions which 

 have exercised the genius of Euler, Lagrange, Poisson, Prony, 

 Cauchy, Weber, Venturi ; and in our own country, of Brindley, 

 Smeaton, Young, Scott Russell, and others. The theory of the 

 Gulf-stream has close connection in many points with these 

 high problems, while at the same time complicated by its 

 manifest relation to the great natural agents just named. 



