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THE POPULAR SCIENCE MONTHLY 



Size of Soil Particles ^ 



Such a loose sandy soil soaks up moisture very readily, so that after 

 a heavy fall of rain scarcely any water is drained from the surface into 

 the valleys, but all of it goes into the porous soil. Now and then rain- 

 storms of such torrential fierceness occur in the hills that a great quan- 

 tity of the sand is brought down from high on the hills and carried into 

 the valleys. Such storms are, however, exceptional, since the itsual 

 heavier rains of about 1.0-1.5 in. are completely taken up by the sand, 

 with no surface drainage at all. 



In connection with the distribution of soil water in the Sand Hills 

 it is interesting to note that, although the surface of the sand is com- 

 monly as dry as powder, the sand but a few inches beneath the surface 

 is quite moist. The average of many soil samples taken during July, 

 1911 (a wet month for that year), in widely isolated stations at a depth 

 of twelve inches, showed the water content to be 3.27 per cent. The 

 Sand Hills rest upon a series of relatively impermeable clays and strati- 

 fied rocks. These layers of more solid materials crop out from the sur- 

 face along streams and on the lower slopes of some hills quite remote 

 from the deeper valleys. The soil is always moister upon a slope with 

 these outcrops than in situations where such are absent. 



The annual precipitation over the main body of Sand Hills varies 

 from twenty-three inches in the east to about fifteen inches on the 

 western border. April, May and June are usually the wettest months 

 of the year, while the dry season frequently continues from August to 

 March or the first of April.^ In the central Sand Hills during the 

 month of July, 1911, five and one half inches of rain fell. At the gov- 

 ernment forest nursery near Halsey (Thomas County) during this 

 month there was scarcely a day that rain did not fall. The showers 

 were usually light, but a few were soaking rains. Hail sometimes accom- 

 panies these thunderstorms in such quantity that a great amount of 

 damage is done to gardens, crops and other property. 



Most of the precipitation disappears into the soil at once. It is a 

 rare sight, if indeed it ever happens, that any of the streams or lakes of 

 the region show an increase in volume resulting from the run-off from 



2 From Professor E. H. Barbour, Nebr. Geol. Survey, Vol. 1, 1903. 

 ^ Data from official records of U. S. Forest Service at Halsey, Nebr., for 

 last seven years. 



