28 CHEMISTRY OF SOIL. 



or effervescence, when poured on pearlash. This 

 action ceasing, there is neither acid taste nor alkaline 

 properties. The characters of the vinegar and 

 pearlash have disappeared. These substances have 

 united, they have formed a new substance called 

 a salt. Their properties are neutralized, and lost in 

 the salt. This is no longer either pearlash or vin- 

 egar. 



47. The fact to be observed in the action (46) is, 

 that an acid and alkali mutually neutralize each 

 other. The vinegar is said, in this case, in common 

 language, to " kill " the pearlash. So soda, potash, 

 lime, magnesia, iron, and manganese would all be 

 killed or neutralized by vinegar ; they would all be 

 dissolved by it, and lose their distinguishing char- 

 acters. In either case, a neutral salt would be 

 formed. Such a class of salts, is termed acetates, 

 being formed of alkalies, alkaline earths, or metal- 

 lic oxides with acetic acid. 



48. Silex or silica, or the earth of flints as it has 

 been called, is in its pure state a perfectly white, in- 

 sipid, tasteless powder. In various combinations of 

 minerals, it unites with the alkaline class (42, 45,) 

 forming neutral salts, termed silicates, from the silicic 

 acid, for silica is an acid formed by the uret silicon 

 with oxygen. Thus is formed, as in the case of 



