LUNGE'S MODIFICATION OF TECHNICAL METHODS 561 



ly all the potash used for fertilizing purposes comes from this 

 region. The methods which are in vogue for the valuation 

 of the product are both of a scientific and commercial importance. 

 Lunge has tabulated these methods in convenient form for refer- 

 ence. 41 The methods as described by Lunge are very nearly the 

 same as those just given, but are modified in some particulars. 



In the investigation of crude salt it is to be recommended that as 

 large a sample as possible be used in order to eliminate any error 

 which might arise from the unequal distribution of impurities in 

 the crude product. The estimation of potash is conducted uni- 

 formly by the platinum method. The description for the method 

 of complete analysis of raw salts is not suitable for this manual 

 but belongs rather in the domain of mineral analyses. It is 

 however, sometimes, of interest to the agricultural analyst to 

 determine the quantity of chlorin and sulfuric acid in the raw 

 salt by reason of the injurious effects which these bodies some- 

 times produce. 



The methods for the complete analysis of these salts are given 

 by Lunge in the article referred to above. The method for the 

 analysis of crude salts for potash alone is as follows: In the 

 case^ of carnallit and bergkieserit 30.56 grams of the salt and for 

 kainit, sylvinit and hartsalz 35.71 grams are boiled in a 500 

 cubic centimeter flask with about 300 cubic centimeters of water 

 and the addition of 15 cubic centimeters of concentrated hydro- 

 chloric acid. After cooling, the flask is filled to the mark. The 

 sulfuric acid in 50 cubic centimeters of the solution or of the 

 filtrate is precipitated in a 200 cubic centimeter flask with barium 

 chlorid and after cooling, the flask is filled to the mark and 20 

 cubic centimeters of the filtrate are treated with a sufficient 

 quantity of the platinum chlorid solution in a flat porcelain dish 

 of about 10 cubic centimeters diameter and, with frequent shaking, 

 the mixture is evaporated on the water bath until the residue 

 is of a sirupy consistence and fumes of hydrochloric acid are no 

 longer evolved. On cooling, the mass solidifies to a crystalline 

 cake. 



The formulation of large crystals of sodium platinochlorid is 



41 Chemisch-technische Untersuchungsmethoden, 5th Edition, 1904, 1 : 

 534- 



