74 Trans. Acad. Sci. of St. Louis. 



It may thus be seen that most of the water whicli falls 

 as rain or snow never reaches the sea through the med- 

 ium of drainage, but is evaporated from the land. If all 

 of the precipitation were led into the rivers and con- 

 ducted back to the sea we should have mighty streams of 

 water which would make our present ones seem as little 

 brooks. 



The discharge of the whole Mississippi system, how- 

 ever, is considerably greater than the river we have im- 

 agined. To make it more definite, the discharge of the 

 Mississippi river at Carrollton, La., was computed for the 

 fourteen years. A discharge curve of the river at that 

 station was constructed from simultaneous gauge read- 

 ings and discharge observations taken from the reports 

 of the Mississippi Kiver Commission. From this curve a 

 discharge curve for each year was constructed, and b}^ 

 mechanically integrating the areas under these curves, 

 the discharge of the river at Carrollton was found for 

 each year. These yearly discharges ranged from 76.3 

 cubic miles in 1895 to 154.7 cubic miles in 1903. The aver- 

 age was 117.0 cubic miles per year, or 545,800 cubic feet 

 per second. This is less than three times the precipita- 

 tion on the state of Missouri. It would be interesting to 

 see what part this discharge is of the whole amount fall- 

 ing upon the area which drains into the Mississippi above 

 its mouth. 



After the precipitation for each state had been com- 

 puted, they were summed up in five districts; the North- 

 east, the Southeast, the North Central, the South Cen- 

 tral, and the Western. The Northeast division comprised 

 the New England States, New York, New Jersey, and 

 Pennsylvania. The Southeast division, Delaware, INIary- 

 land. West Virginia, and the South Atlantic States. The 

 North Central, Ohio, Indiana, Illinois, Wisconsin, Mich- 

 igan, Minnesota, Iowa, Missouri, North Dakota, South 

 Dakota, Nebraska and Kansas. The South Central, Ken- 

 tucky, Tennessee, Alabama, Mississippi, Arkansas, 



