5O2 AGRICULTURAL ANALYSIS 



the saving in freight often more than compensates for the higher 

 price of the potash. It therefore happens that there are many 

 places in this country where the actual price of potash per pound 

 is less in high grade sulfates than in kainit or carnallit. When, 

 in addition to this, the especial fitness of the high grade sulfates 

 for certain kinds of fertilization, especially tobacco growing, is 

 considered, it is seen that at this distance from the mines these 

 high grade salts are of no inconsiderable importance. The per- 

 centage of potash in the high grade sulfates often exceeds 50. 



431. Potassium-Magnesium Carbonate. This salt has lately 

 been manufactured and used to a considerable extent, especially 

 for tobacco fertilizing. As furnished to the trade it has the fol- 

 lowing average composition : 



Per cent. 



Potassium carbonate 35 to 40 



Magnesium carbonate 33 to 36 



Water of crystallization 25 



Potassium chlorid, potassium sulfate, and insoluble- 2 to 3 



The content of potash, as is seen from the above formula, 

 amounts to from 20 to 25 per cent. The compound is completely 

 dry, is not hygroscopic, and is, therefore, always ready for distribu- 

 tion. It is especially to be recommended for all those intensive 

 cultures where it is feared that chlorids and sulfates will prove 

 injurious, especially in the cultivation of tobacco. 



432. Potash in Factory Residues. The residues from the potash 

 factories in Stassfurt and vicinity contain considerable quantities 

 of potash and attempts have been made to recover this waste and 

 put it into form for fertilizing uses. The waste waters of the 

 factories are sometimes collected and evaporated, and the residue 

 incinerated. The content of potash in these residues is extremely 

 variable, usually quite low, and they, therefore, can not be recom- 

 mended for fertilizing purposes, especially if they are to be trans- 

 ported to any distance. 



433. Production of Crude Salts. The following table gives 

 the production of crude salts, in the Stassfurt region from 1888 

 to the close of 1901 : 



