MANURE. 163 



ash ; 2dly, that from hard soap, barilla, or soda ash. 

 A boil of 2000 lbs. of soft soap, requires 150 bush- 

 els of ashes, and its spent ley contains, in addition to 

 a little free potash, the following salts, derived from 

 the ashes : 



130 lbs. of Sulphate of potash, 



6 " of Muriate of potash, 

 36 " of Silicate of potash, 



allowing the ashes to have been a mixture of oak, 

 bass, and birch woods. Besides these, in the process 

 of soap making, in order to make the soap " grain," 

 common salt is added. A chemical change is thus 

 induced, the potash soap, is changed to soda soap, 

 or the soft to hard. The soda of the salt en- 

 tering the soap is replaced by the potash, which com- 

 bines with the acid of the salt, that is chlorine or 

 muriatic acid. In other words, common salt, or 

 chloride of sodium, or muriate of soda is changed 

 to chloride of potassium, or muriate of potash, which 

 is thus added to the spent ley. The proportion of 

 salt added, varies, but it may be stated in general, 

 7 bushels, or 500 lbs. to 150 bushels of ashes. In 

 a boil, then, of 2000 lbs. of soap, 1200 lbs. of fat 

 or tallow, containing 100 lbs. of glycerine, 

 150 bushels of ashes, 



7 bushels of salt, 



