106 TBANSACTIONS OF THE ILLINOIS 



bottom to receive water. Each was filled with the same kind of 

 soil, containing 14.3 per cent, of water. Both were filled with soil, 

 firmly pressed, to within two inches of top, the amount of soil used 

 differing by only three ounces. One can was filled to top with soil 

 firmly pressed and the other filled with loose soil, the latter intended 

 to be cultivated. To each was added two pounds of water, one pound 

 being poured on surface of each and the other placed in receptacle 

 at bottom. Each were then placed in sun, and each lost at end of 

 three days 8 oz. of water. The surface of the one was then culti- 

 vated 1^ inches deep daily. At end of seven days the cultivated soil 

 had lost 5 oz. and the uncultivated 9^ oz. of water. The water saved 

 during a week on an acre of land by cultivation would be 30 tons, 

 or would be equal to about one-fourth inch of rainfall. 



LOSS OF WATER BY DRYIXG IN AIR. 



Sixteen samples of soil containing an average of 14.3 per cent, 

 of water were put in pans having an exposed surface of | square 

 foot and a depth of one inch. They were exposed in a still room to 

 the direct rays of the sun, the temperature of the room averaging at 

 mid-day about 90° F. The average loss of water in two days was 

 6 11-16 oz. or 8.4 per cent, of the weight of dry soil, and 58.7 the 

 total amount of water contained. This gives some idea of the 

 amount of water that must be raised by capillary attraction, during 

 drouth, in order to keep soil in moist condition. 



Two pounds of water were applied to each of four samples of 

 dry soil weighing 5 pounds each, and the surplus water allowed to 

 drain away. At the end of eight hours, drainage ceased and there 

 remained from 46.8 to 52.0 per cent, of water, with an average of 

 49.3 per cent. A saturated soil may contain, therefore, about half 

 its weight in water. 



SUMMARY. 



Eighty samples of soil, forty from first foot in depth, and forty 

 from second, taken in Champaign, Marion and Hancock counties 

 between Aug. 1st and 19th, 1887, gave an average of 13.2 per cent, 

 of water. This in two feet of soil is equal to four inches of rain- 

 fall or 110,000 gallons of water per acre. This is about equal to 

 the average monthly rainfall in this region, and is over four times 

 the rainfall in Champaign County during the two months previous 

 to making the tests, as reported by the observer for the Illinois 

 State Weather Service. 



Forty-four samples taken in Champaign County gave an average 

 of 13.5 per cent, of water. This is a little more than one-fourth 

 the amount contained by a thoroughly saturated soil. Twenty-two 

 samples of first foot contained on an average 12.0 per cent, and a 

 like number of second foot 15.0 per cent, of water. The lowest 

 per cent, of water found in first foot of soil was 8.5. It was found 



