120 Mr Ellet on the Proper Application of 



not intended to be wholly exhausted ; and need only to be 

 reduced at the surface, so as to lay bare a portion of their 

 rocky borders. 



But the salubrity of rivers, when no longer subject to be- 

 come dry, and have their sands and vegetable deposits ex- 

 posed to the summer's sun, must necessarily be increased ; 

 for the same experience which teaches that large masses of 

 fresh water, existing as lakes, are salubrious, also teaches 

 that shallow, stagnant pools, such as are found in the place 

 of an exhausted river, are deleterious to health. 



It is difficult to imagine a serious objection to the im- 

 provement of this great natural system of inland navigation, 

 by a method which accomplishes so much for an outlay so 

 small — by a plan which places no incidental impediment in 

 the way of trade, and the application of which is limited to 

 no State or section of the Union. 



From the base of the Rocky Mountains to the base of the 

 Alleghany, there is not a great river or navigable tributary 

 that may not be benefited by this process ; while on the 

 eastern slope of the dividing range there are numerous rivers 

 flowing into the Atlantic, which have been improved by other 

 means, and which must ultimately be subjected to this treat- 

 ment, and relieved of the dams by which they are now ob- 

 structed. 



The North Branch of the Susquehanna may be easily 

 made navigable, from its mouth into the State of New York, 

 for a convenient class of steamboats, by this simple expe- 

 dient ; and there are several rivers in Virginia, which, for 

 an insignificant cost, may probably be supplied with abun- 

 dant water for a permanent navigation. 



The personal observation of the writer does not extend to 

 the great rivers of the Southern States. But the elevations 

 of their surfaces above tide, from point to point, seem to in- 

 dicate that they are even more susceptible of the application 

 of this method of improvement than those farther north; 

 while the Cumberland and Tennessee, and the rivers of 

 Kentucky, possess all the essential characteristics of the Ohio, 

 and will always afford a good navigation for steamboats, 

 whenever they are adequately supplied with water. 



