ON THE MISSISSIPPI. 1D9 



ary the water will rise still higher by an additional height cor- 

 responding to the superficial velocity: thus Pitot's tube placed 

 at the depth of 1G feet in a river whose superficial velocity is 

 8 feet per second, would raise the water to the height of 1 7 feet 

 above the surface of the river, and orifices being made in the side 

 of the vertical tube, the water would liow out with various veloci- 

 ties depending on the position of the respective orifices. What a 

 discovery this for raising of water without machinery ! ! how- 

 ever absurd this result may appear, it is fairly deducible from 

 the theory. 



In any great river, water flowing in the direction 1, 2, 3, (Fig. 

 5.) and impinging against the bank at 3, will there accumulate 

 and rise higher than at 4 (which is always lower than at 2,) if 

 the velocity of the current be 8 feet per second, it will have a 

 tendency to rise one foot, but from the unconlined state of the 

 water, a considerable abatement will take place; the water ac- 

 cumulated at 3, is the cause of all eddies; it falls off in all di- 

 rections from the thread of the current, producing always an 

 accelerated current in the direction 3, 5 ; an eddy will be 

 formed from 3 to 4 and a portion of the flood passing over to 

 6, not unfrequently causes a smaller eddy from 6 to 7 ; in 

 favoring situations the eddy from 3 to 4, appears sometimes to 

 rival the strength and velocity of the principal stream : dange- 

 rous whirlpools are frequently produced in the situation w, oc- 

 casioned by the counter currents; such a one exists at the grand 

 gulf in the Mississippi, and in many other situations: we have 

 seen one of about 5 feet diameter and 3 feet deep; all floating- 

 bodies passing within a certain distance of the vortex are at- 

 tracted by it, and if not too large and buoyant, are precipitat- 

 ed to the bottom of . the river, rising at the distance of 50, 

 100 or more yards from the place of descent: this imaginary 

 energy of deep rivers, the result only of the descending fluid 

 will nevertheless be extinguished as soon as the declivity of the 

 surface is lost; rivers running a long course through an alluvial 

 country, without the influx of auxiliary streams, are liable to 

 stagnate before their junction with the ocean; the Nile is a re- 

 markable example of this kind : and even the Mississippi, al- 

 though we have said in general that it rolls a great body of 



B 



