THE MISSISSIPPI VALLEY. 25 



was possible to curb, and render harmless, the floods which now annually 

 sweep through the western valleys. 



On seeking to find how much water would be needed to maintain the naviga- 

 tion at any given height, it became important, further, to determine the maximum 

 height at which it could be permanently held — a question of vast importance to 

 the mind that views the interior navigation of this country but as a continuation 

 of that of the ocean ; and is directed forward to the day when every city upon 

 the banks of the Mississippi, Missouri, and a portion of the Ohio, is to become a 

 port of foreign entry, accessible to ocean steamers; when the forests of the inte- 

 rior are to furnish the timber, the mines of the interior the iron and coal, the 

 w^orkshops of the interior the machinery of the vessels, and the fertile plains of 

 the Mississippi valley the freight, which is to be shipped from the seaports of 

 the intei'ior to the markets of the world. 



The commercial position and advantages of this wonderful valley are sublime; 

 and its physical capabilities deserve a far more perfect investigation than can be 

 expected of private zeal. Still, the purposes of the writer required the solution 

 of this interesting problem ; and he was therefore compelled to compute, day by 

 day, the discharge of the river for the whole year ; and to render the I'esults 

 more worthy of confidence, for a continuous period of six years. 



The same train of inquiry necessarily led to the determination of the annual 

 drainage, and its comparison with the annual fall of rain over the wide district 

 covered by the tributaries of the Ohio ; and, as a consequence, the annual con- 

 sumption of water in the processes of vegetation and evaporation. 



These results are briefly stated in this paper; and being deduced from an 

 area of nearly 25,000 square miles, and for a series of years, they possess an 

 interest much greater than could attach to any local or more limited inquiry. 



It will be found that the expectations which led to the laborious undertaking 

 have been fully confirmed ; that the steamboat navigation of the Ohio may be 

 permanently maintained for a very trifling outlay ; and that the power of the 

 floods also may be greatly reduced by an incidental application of the reservoirs 

 which will support the navigation. The results show that it is quite practi- 

 cable to maintain an uniform height of water in this river, and that that height 

 may be ultimately raised, at Wheeling, to nine feet. (See note A.) But these 

 more remote applications are not discussed here. The present inquii*y is limited 

 to things immediate — valuable to science, or useful to the public welfare. 



