114 ACTION OF SALTS. 



er it is, it adds so much to the value of the leached 

 ashes. Besides the soap-maker always leaves a por- 

 tion of alkali, which is combined with the silex. 

 Exposure to air decomposes this, and then the alkali 

 can be extracted by water. This is one great source 

 of the active power of leached ashes. 



164. A bushel of good ashes contains about 5 1-2 

 lbs. of real potash. In leaching ashes, generally 

 about 1 peck of lime is added to each bushel of 

 ashes, and as it loses no bulk during the operation, 

 a cord of leached ashes contains about the following 

 proportions, allowing the usual proportion to be 

 leached out. or 4 1-2 lbs. 



Phosphoric acid, 117 lbs. 



Silex, 146 * 



Oxide of iron, 17 " 



" of manganese, 51 " 



Magnesia, 119 " 



Carbonate of lime, including that add- 

 ed in leaching, 3072 ■* 

 Potash combined with silica, 50 " 

 Spent ashes, therefore, belong to the class of car- 

 bonates. 



165. It may be here remarked in relation to sili- 

 cate of potash, that this substance forms a greater 

 part of the residuum produced in the conversion of 



