POTASSIC MANUEES. 



311 



The following according to analyses now old are the chlorine 

 content of crude Stassfurt salts : — 



TABLE CVIL— CHLORINE CONTENT OF CRUDE POTASH SALTS. 



More recent analyses of kainit in the agricultural experiment 

 stations have shown for a long time that the proportion of chlorine 

 has been continually increasing. 



Thus, in 1895, B. Sjollemay found 35-8 of chlorine. In 1896, 

 Adolphe Mayer found still higher figures. In 1908, chlorine and 

 potash were estimated in fifty-nine samples. A single sample alone 

 gave the same chlorine content as formerly : — 



It is, therefore, established that kainit has not the same composi- 

 tion as formerly. It would appear to be mixed with minerals rich 

 in potash and with a high chlorine content. A more complete 

 analysis of the kainit showed that some samples only contained 

 1"50 per cent of sulphuric acid. Potassium chloride (muriate of 

 potash) contains 50 per cent of potash and 50 per cent of chlorine. 

 In a number of samples of kainit the chlorine content was also 

 50 per cent, but the potash content was only one-fourth of the 

 amount contained in potassium chloride. In this way it would be 

 necessary to use four times more of a manure of this kind to obtain 



