DISCUSSION OF CHEMICAL DATA. 



91 



MALIC- ACID VALUE. 



The two methods yielded values whose average differed by about 

 0.2. The word " value" is properly used in this connection, as 

 the methods do not purport to separate the malic acid completely. 

 Calcium, either as the chlorid or acetate, in the presence of alcohol, 

 will precipitate other acids, and hence the figure obtained does not 

 represent true malic acid. No sufficiently quick and accurate 

 method for separating and determining this acid in the presence of 

 other acids and of organic matter is known. 



The average of all determinations made by the modified calcium 

 chlorid method of the Association of Official Agricultural Chemists 

 is 0.84, the maximum being 1.60 and the minimum 0.29; by the cal- 

 cium acetate method the average is 1.01, the determinations varying 

 from 1.82 to 0.21. 



The tabulated results of the two methods, arranged by States and 

 grouped, are given in the following table: 



Malic-acid value determined by two methods and results grouped by States. 

 ASSOCIATION METHOD. 



COWLES METHOD. 



a 0.29 malic-acid value. 



6 One determination lost. 



0.21 malic-acid value. 



