216 WALL'S MANUAL 



Many marls contain green sand-grains, a mineral 

 containing a large quantity of potash and soluble 

 sand, and therefore especially adapted to the cereals 

 and grasses, 



POTASH, 



Potash of commerce, is obtained from the lye of 

 wood ashes, boiled down in pots ; hence, the name of 

 potash. It is used chiefly in the manufacture of soap 

 and glass. Ashes of wood are used largely in agri- 

 culture ; one bushel of good wood ashes, contains 

 about four and a half pounds of pure potash. 



AXALY8IS OP ASHES (100 POUNDS) OP BECH AND PINE WOOD, 



(Bottinger,) (Malaguti.) 



Beech, Pine. 



Potash 11.80 16.24 



Soda 2.04 5.26 



Magnesia 8.42 7.12 



Chloride of soda 0,16 1,65 



Sulphuric acid 1.01 10.29 



Carbonate of lime 47.21 44.74 



Phosphoric acid 2,29 6.11 



Silica 1.09 6.81 



Oxyde of iron 0.60 1.60 



100,00 100.00 



It will be perceived from the above analysis, that 

 woods ashes contain an average of about twelve per 

 cent, of potash, three and a half per cent, of soda, five 

 and a half per cent, of sulphuric acid, all soluble in 

 water. The insoluble parts are bases, and when they 

 come in contact with the mold and acids in the soil, 

 become soluble, causing the insoluble humus or mold 

 to become soluble, and, therefore, food for plants. 

 Hence, the value of wood ashes as a fertilizer. 



SODA. 



Soda is readily distinguished from the other 

 alkalies by the following characteristic* : "With 



