EXPERIMENT STATION BULLETINS. 851 



change in depression, required only 1 c. c. after it received 10 c. c. 

 N/25 Ca(0H)2 



2 gm. Soil No. 3 originally required 5.5 c. c. N/25 KOH to cause 

 change in the depression, required only 1 c. c. after it received 9 c. c. 

 N/25 Ca(0H)2. 



2 gm. Soil No. 1 originally required 6 c. c. N/25 Ca(OH)o to cause 

 change in depression, required only 1 c. c. after it received 6 c. c. 

 N/25 KOH. 



2 gm. Soil No. 2 originally required 9 c. c. N/25 Ca(0H)2 to cause 

 change in depression, required only 1.5 c. c. after it received 6 c. c. 

 N/25 KOH. 



2 gm. Soil No. 3 originally required 8.5 c. c. N/25 Ca(0H)2 to cause 

 change in depression, required only 1.5 c. c. after it received 6 c. c. 

 N/25 KOH. 



It becomes at once evident from the above tabulated data, therefore, 

 that when a soil is saturated or satisfied with a particular base it will 

 absorb very little if any of another base, even though the various bases 

 are absorbed in non-equivalent amounts. 



On the other hand, when a soil is only partly satisfied with one base it 

 will take up a correspondingly large amount of another. Thus for in- 

 stance, when a soil in 2 gm. portion required and received 3.5 c. c. 

 N/25 KOH, the addition of only 1 c. c. N/25 CaCOH). caused a change 

 in the depression. On the other hand, when only 2.5 c. c. N/25 KOH was 

 added to this soil, it required 7 c. c. N/25 Ca(0H)2 to cause a change in 

 the depression. This was true in the case of all bases. 



Just what is the true explanation of this unequal absorption of the 

 various hydrates by the same kind of soils cannot be stated at this time. 

 It is evident, however, that it follows some definite and significant laws. 

 The problem is under special investigation and it is hoped the true ex- 

 planation will be discovered. 



Finally, it should be stated that this unequal absorption of the various 

 hydrates, does not appear at present to be a point against the freezing 

 point method, for determining the lime requirements of soils. On the 

 contrary, it points to some phenomena which promise to be of significant 

 theoretical interest and of important practical value. 



EFFECT OF ACIDS AND ACID SALTS UPON THE LIMB REQUIREMENT OF SOILS. 



Thus far the lime requirement of only natural untreated soils has 

 been considered. The question will now be taken up of the effect of 

 acids, acid salts, and neutral salts upon the lime requirement of soils. 

 Since the data dealing with the acid and acid salt treatments illustrate 

 certain fundamental principles which are necessary for a convenient and 

 successful discussion of the data pertaining to the neutral salt treat- 

 ments, they will be considered first. 



The research on the effect of acids, and acid salts upon the lime re- 

 quirement of soils consisted (1) of adding to 2 grams of soil various 

 amounts of inorganic and organic acids, and inorganic acid salts and 

 then determining its lime requirement; and (2) treating the soil with an 

 excess of acid, then washing it with water, drying it in the air, and its 

 lime requirement determined. In Table 9 there are presented the lime 



