46 PHYSICAL GEOGRAPHY. 



inches probably not more than five inches soaked into the ground. 

 Cultivated soil, however, absorbs nearly all the rain that falls. 

 Where thirty-two inches of rain now falls in Nebraska on cultiva- 

 ted ground, not less than twenty-four inches are absorbed by the 

 soil. Some of this is slowly given back into the atmosphere, and 

 some of it goes to form the new springs of water that are making 

 their appearance in so many places. Any one can see that this 

 must make an enormous difference in the moisture of the atmos- 

 phere and on rainfall. Before the settlement of the State, and be- 

 fore the consequent cultivation of the soil, what rain did fall, as 

 already stated, soon left the State through creeks and rivers. Now 

 the greater part of what does fall on all cultivated or broken ground, 

 is retained by the soil which becomes a reservoir of water to sup- 

 ply growing crops, and to give greater humidity to the atmosphere. 



Absorptive Power of Nebraska Soil. 



No soil in the Eastern States has so great an absorptive power 

 as the land in Nebraska. There, as a general rule, the underlying 

 hard rock is soon reached, and during excessive rains the thin soil 

 is so supersaturated with water that excessive denudation of the 

 soil is common. A thin soil also dries out, because there are no 

 stores of moisture below from which it can draw supplies. Here, 

 however, the superficial deposits are of very great thickness. The 

 loess itself, ranges from two feet to two hundred feet, and often 

 where it is thin, there are below it great bodies of drift. The av- 

 erage thickness of all the superficial deposits — loess and drift — 

 is considerably over one hundred feet. This thickness, therefore, 

 of surface materials constitutes the huge sponge that absorbs ex- 

 cesses of rainfall, and retains it to be given back to the atmosphere 

 only gradually. 



Here, then, we have a cause competent to account for the in- 

 creased rainfall of the State — a cause that not only has operated 

 thus far but is continuous. Through the operations of this cause, 

 the rainfall will become even more abundant than it has yet been, 

 especially over the central and western portion of the State. The 

 area of cultivation is extending rapidly each year, and continual en- 

 croachments are made on the lands in western Nebraska, that have 

 been condemned as barren because of a deficiency of rainfall. Last 

 year a large amount of land breaking was done near to and west 

 of the iooth meridian in the Republican Valley and the table lands 



