24 



In this condition the moist soils were transferred to 2-quart 

 Mason fruit jars, the mouths of which were closed, with a plug 

 of loose cotton wool, to check evaporation but permit normal 

 aeration. The jars were then weighed and set aside. Once 

 each week, after starting the experiment, the plugs of cotton 

 wool were removed, the jars covered, inverted and shaken to 

 secure a thorough exchange of air throughout the entire volume 

 of soil. 



Considering the weight of the moist soil for each soil type 

 to be 4,000,000 Ibs. per acre-foot and the manure to carry 70 

 per cent, of water, the amounts added, supposing them to be in- 

 corporated with the surf ace > 6 inches of soil only, were at the 

 rates of 25.22, 50.43, 100.87 and 201.73 tons per acre. 



A partial gravimetric analysis of the manure used, made by 

 Dr. Schreiner, gave the results stated in the table. 



Composition of manure used. 



In percent, of the dry manure. 



The Mason jars with their soil content were weighed from 

 time to time during the interval of the experiment and enough 

 water added to restore that lost by evaporation, and on Sep- 

 tember 10 and 11 the samples were examined for the water- 

 soluble salts which could be recovered from them by single 

 washings during three minutes. The results obtained are 

 given in the following sections. 



