ON THE MISSISSIPPI. 197 



it will be found from the above mode of reasoning, that the 

 superficial velocity gained would be at the rate of 8 feet per 

 mile: it is unnecessary to advance any thing further against a 

 theory capable of yielding results so contradictory among them- 

 selves, and so totally at variance with fact and observations. 



From what has been said we may conclude that the natural 

 movement of fluids depends solely upon the declivity of the 

 surface; the obstructions arising from friction, adhesion and 

 vicidity, being greatest at the bottom and sides, the velocity of 

 the current will consequently be greatest at the surface and in 

 the middle of the channel where there is no deflecting cause. 

 Buat observes, we may be assured that the central filament of 

 water running through an inclined cylindric glass tube flows 

 with the greatest velocity, it being known that however smooth 

 and polished the interior surface of the tube may be, the retard- 

 ations from friction are very considerable; if we suppose the 

 superior half of the cylinder to be removed with its included 

 water, the relative velocities of the inferior half will continue 

 the same, and he sees no reason to doubt that all rivers and ca- 

 nals move upon the same principles. We shall consider this 

 object in anotber point of view, leading to the same conclusion. 

 Let the solid A B, (Fig. 3.) of indefinite length, be divi- 

 ded into a number of very thin and polished lamina?, and 

 placed upon the inclined plane B C, with such declivity as 

 that the solid may just begin to move by the power of gravity 

 down the inclined plane from B, towards D, when the lamina 

 1, shall have gotten into the position I, the lamina 2, possessing 

 a greater facility of motion over 1, than this last has over the 

 inclined plane, will have also made one step over 1, and will 

 be found in the position II; in like manner, the lamina 3, will 

 at the same instant move over the lamina 1, and make one step 

 beyond it and will be found in the position III, and so of all 

 the other superior laminae which will be found respectively in 

 the situations represented in the figure. Water being composed 

 of parts possessing extreme mobility, it is not unreasonable to 

 conclude that its motion along an inclined plane, will be some- 

 what analagous to that of polished lamina?, but as fluids press 

 laterally as well as perpendicularly, there must be correspond- 



