CHAPTER V 

 TESTS FOR ACIDITY 



The Litmus Paper Test. A method of 

 testing soils for acidity, which has been in 

 use for many years, is the simple litmus 

 paper method. Because of its simplicity 

 and fair degree of accuracy, the litmus 

 paper test is still used to a considerable 

 extent in estimating the degree of acidity of 

 certain soils. The best manner of using 

 litmus is to place a strip of the blue paper 

 in the bottom of a glass saucer, covering it 

 with filter paper or other paper which is 

 neutral that is, paper which is neither 

 acid nor alkaline. 



A small quantity of the soil to be tested is 

 moistened with rain or distilled water and 

 placed on this paper. If the acid is present 

 the blue paper will be changed to a reddish 

 color, varying in intensity according to the 

 degree of acidity in the soil. Two objec- 

 tions to the use of litmus paper are to be 

 noted: One of these is that the red color 

 may be produced by carbonic acid gas with- 

 out a trace of more powerful acids being 



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