RAINFALL IN NEBRASKA. 45 



absorbed by the soil like a huge sponge. The soil gives this ab- 

 sorbed moisture slowly back to the atmosphere by evaporation. 

 Thus year by year as cultivation of the soil is extended, more of the 

 rain that falls is absorbed and retained to be given off by evapora- 

 tion, or to produce springs. This, of course, must give increasing 

 moisture and rainfall. 



In order to test the accuracy of this theory, which struck me as 

 the only true explanation of this phenomenon as early as 1867, I, at 

 various times, made some experiments. The first accurate experi- 

 ments I made in May, 1872. I went east of the Antelope, about a 

 mile, from Lincoln, to a farm now owned by Mr. Hawley, after a 

 heavy rain. With a rule, six inches square was marked off, of un- 

 broken prairie, and this was taken up six inches deep and placed in 

 a porcelain dish that had been previously weighed. The same 

 amount to the same depth, was taken from a cultivated field. The 

 difference in weights between the two specimens was sufficiently great 

 to prove that the cultivated land absorbed at least during this rain, 

 twelve times as much moisture as the uncultivated. The 

 specimens were taken from lands only a few yards apart. After 

 another rain, from near the same locality, a square foot three inches 

 deep, was lifted and compared with a-n equal amount from an ad- 

 joining field. The specimens were first weighed, then dried and then 

 weighed again. The difference in this case indicated that ten times 

 as much moisture had been absorbed by the cultivated ground as by 

 the unbroken prairie. In June, 1873, similar experiments were 

 made and with the same results. Where the rainfall is slight, the 

 difference will not be found to be so great. Much also depends on 

 the lay of the land ; care must also be taken that the cultivated 

 land that is experimented with, lies adjoining unbroken 

 prairie, as there is often considerable difference in rainfall, espec- 

 ially in thunder storms, in the space of a quarter of a mile. In all 

 cases the experiments were made immediately after or during the 

 intermissions of rainfall. After only slight rains, the difference in 

 absorptive power was only as four to one. The mean, however, of 

 fifty of these experiments, gives an average absorptive power of 

 cultivated ground over unbroken prairie of nine to one. To make 

 allowances, however, for possible mistakes, I will make eight to one 

 the basis of our future calculations on this subject. 



When the first settlements were commenced in Nebraska the 

 rainfall of the State was not over twenty inches. Of these twenty 



