Superphosphates Potash 99 



Potassium carbonate. 



Potassium carbonate is used to some extent as a fer- 

 tilizer and sometimes upon compost heaps. Investiga- 

 tions show that it is well adapted to tobacco-growing. It 

 is a high-grade product containing 65 per cent of actual 

 potash. 



Potassium nitrate. 



This material already mentioned would be especially 

 valuable for agricultural purposes were it not for its 

 greater value for use in the manufacture of gunpowder 

 and explosives which makes it more expensive than the 

 combined cost of the separate ingredients in other salts. 

 It is also called nitrate of potash, niter and saltpeter, and 

 contains 14 per cent of nitrogen and 44 per cent of actual 

 potash. 



Feldspar and other minerals as a source of potash. 



Feldspar and a large number of other minerals including 

 leucite, alunite, phonolite and nepheline have caused 

 much thought and experimentation upon the part of 

 chemists and investigators for a number of years as prob- 

 able sources of potash. So far, little of practical impor- 

 tance has been accomplished with these minerals because 

 no methods have been developed which would success- 

 fully extract the potash, and pulverization even to ex- 

 treme fineness does not render potash contained in them 

 available. 



Formations of alunite recently found at Marysvale, 

 Utah, caused considerable comment at the time of their 

 discovery ; but, here again, the manufacture is still in the 

 experimental stage. Nor has leucite, which contains 18 

 to 20 per cent of actual potash, been found practicable. 



