ANALYSIS OF CARNALUT, KAINIT, ETC. 553 



been decomposed by the ignition, the percentage of chlorin is 

 determined by titration. The difference in the contents of chlorin 

 before and after ignition is subtracted from the loss in weight, 

 after allowance has been made for the absorption of oxygen and 

 for the loss of hydrogen. The rest is water. Or, in order to 

 avoid the loss of chlorin, the sample is covered by a known 

 quantity of freshly ignited burnt lime or lead oxid to absorb the 

 chlorin from the magnesium chlorid. 



Calculation of Composition. The results obtained are calcu- 

 lated in the following manner: From the total amount of the 

 sulfuric acid found, that portion is deducted which is combined 

 with calcium as calcium sulfate ; the rest of the sulfuric acid is 

 divided into two equal parts for the purpose of calculating the 

 contents of potassium sulfate and magnesium sulfate, according 

 to the molecular proportion in which these salts are present in 

 kainit and in schonit. If there be an excess of potash left un- 

 combined with sulfuric acid, then it is in the form of potassium 

 chlorid ; likewise, the amount of magnesia, uncombined with sul- 

 furic acid, is to be reckoned as magnesium chlorid. The result 

 of this calculation will tell how much potash is in the form of 

 kainit (K,SO 4 , MgSO 4 , MgCl,, with 6H 2 O) and how much of 

 it is in the form of schonit (K 2 SO 4 , MgSO 4 , with 6H 2 O) and 

 how much in the form of potassium chlorid. The sodium is reck- 

 oned as sodium chlorid. 



In the case of hartsalz, the water content of which is only 

 about one-third of that in kainit, the potassium is calculated as 

 chlorid. When longbeinit (K 2 SO 4 ,2MgSO 4 ) is present with 

 kainit, the magnesia and lime present are credited as sulfates, 

 the excess of sulfuric acid remaining being then reckoned as 

 a potassium salt. Should a complete examination and identifica- 

 tion of the various minerals present in a more complicated mix- 

 ture of the crude salts be required, this cannot be performed from 

 calculations founded simply upon a quantitative chemical analysis 

 of the various constituents. In such a case for example the mag- 

 nesium chlorid soluble in alcohol should be determined, as from 

 this the proportion of carnallit may be reckoned. Further aid 



