822 STATE BOARD OF AGRICULTURE. 



for lime, i. c, it is already alkaline and satisfied, then the freezing point 

 depression starts to ascend almost immediately upon the addition of a 

 small amount of Ca(0n)2. These principles are clearly illustrated by 

 the following examples. 



The first principle, that the freezing point depression of a soil contain- 

 ing a soluble acid or acid salt decreases with increased amount of 

 Ca(0H)2 added until the point of neutralization is reached and then 

 begins to increase, was established (1) by pure acids and acid salts, 

 and (2) with soils to which were added acids and acid salts. 

 In Table 1 there are shown the freezing point depressions of HCl, HoSO^, 

 H2C2O4 and Al.CNOg)^ in pure solutions titrated with Ca(0H)2. These 

 results are graphically rejjresented in figures la, lb, Ic and Id. In 

 order to avoid the factor of dilution of the reagents, the acids and acid 

 salts were sufficiently diluted to make their freezing point depression 

 much smaller than that of the Ca(0H)2 whose depression was .105° C. 

 It should be stated that the results below are presented solely to illustrate 

 the principle and not necessarily the exact neutralization point. 



TABLE 1. THE FREEZING POINT DEPRESSION OF HCl. H2SO4, H2C2O4 AND AlsCNOa)! 

 TO WHICH WERE ADDED DIFFERENT AMOUNTS OF Ca(OH)2. 



Reagents. Depression 



HCl 055°C 



plus 2 c. c. Ca(0H)2 045 



plus 1 c. c. Ca(0H)2 040 



plus 1 c. c. Ca(OH)2 039 



plus 1 c. c. Ca(OH)2 041 



plus 1 c. c. Ca(0H)2 045 



H2C2O4 04000 



plus 3 c. c. Ca(0H)2 021 



plus 2 c. c. Ca(OH)2 010 



plus 2 c. c. Ca(OH)2 000 



plus 1 c. c. Ca(OH)2 002 



plus 5 c. c. Ca(OH)2 025 



H2SO4 048''C 



plus 3 c. c. Ca(OH)2 030 



plus 1 c. c. Ca(OH)2 029 



plus 1 c. c. Ca(0H)2 031 



plus 4 c. c. Ca(OH)2 ; .046 



Al2(N03)6 060°C 



plus 2 c. c. Ca(0H)2 057 



plus 4 c. C. Ca(OH)2 050 



plus 2 c. c. Ca(OH)2 051 



plus 5 c. c. Ca(0H)2 061 



An inspection of the foregoing results bears out perfectly what has 

 already been said, namely, the freezing point depression of the acids and 

 acid salts decreases as more and more Ca (0H)2 is added to them until 

 a certain point, the neutralization point, is reached and then it com- 

 mences to increase with further addition of the hydrate. 



Now it will be of interest to know whether the same general results 

 are obtained when these acids and acid salts are added to the soil and 

 the titration is done in the soil. Table 2 contains the results of a few 

 typical experiments bearing upon this point. These results are graphically 

 represented in figures 2a, and 2b. The experiments consisted of adding 

 10 c. c. of the acids or acid salts to 2 grams of soil and then following the 

 same procedure as in the case of the pure solution. 



