'24 DEPARTMENT OF AGRICULTURE GEORGIA. [310] 



Potash is a combination of oxygen and a soft, white 

 metal called potassium. 



This metal cannot exist in the air, and, if thrown on 

 water, burns with a bright purple flame. 



Potash is obtained by leaching the ashes of hickory, oak 

 and other hardwood trees in the form of lye, from which 

 the water may be evaporated, leaving crude potash. This, 

 when somewhat purified, is called pearl ash, which is a 

 compound of carbonic acid and potash, or carbonate of 

 potash. Potash is spoken of as caustic, on account of its 

 strong corrosive action on the skin. It is one of the strong- 

 est alkalies, and forms salts with all acids. 



It is an essential ingredient of plants, from which it is 

 obtained in the form of carbonate of potash, though it 

 does not exist in that form in plants, but is there usually 

 united with some vegetable acid. 



Its chief source in soils is from feldspathic and micarious 

 rocks, and the decomposition of vegetable matter. 



Its principal commercial source is the kainit, which is 

 mined at Strassfurt, Prussia, the composition of which 

 is as follows : 



Sulphate of potassa from 28 to 32 per cent 



Sulphate of magnesia from 14 to 20 per cent 



Chloride of magnesium from 4 to 5 per cent 



Sulphate of lime from 10 to 12 per cent 



Chloride of sodium from 35 to 40 per cent 



This deposit was struck at a depth of from 480 to 812 

 feet. The thickness of the bed is still unknown, though 

 it has been pierced over 1,000 feet. It extends over an 

 area of twenty-five German miles in length. 



Chloride of Potassium, known also as muriate of potash* 

 is found near Strassfurt, in Prussia, where it exists in a bed 

 of clay, overlying a bed of rock salt, 100 feet in thickness. 

 Nearly one-fourth of the weight of this clay is chloride of 

 potassium. It is considered the cheapest, though proba- 

 bly not the best, source of potash for agricultural purposes. 



