84 LITHIA. 



Borate ofsoda^ or borax, and 



P/fOsphaie of soda, useful as a test. 



The fixed alkalies readily combine with oils, and 

 tluis form soap. Soap is soluble in water, and 

 owes its detergent quality to the alkali contained in 

 it. Alkali by itself would be too powerful, and 

 would be apt to destroy the linen and other sub- 

 stances to be cleaned. 



Soap when in solution is decomposed by acids, 

 which unite with the alkali ; hence if an acid is 

 contained in water, the soap curdles. Neutral 

 salts formed by acids with bases of the earths pro- 

 duce the same effect. Hard waters are such as 

 have earthy salts, and are unfit for washing ; soft 

 water is that which is quite free from salts. 



Hard soap is made from soda rendered caustic 

 by lime, and olive-oil, or tallow. Soft soap is com- 

 posed of potash and whale-oil. 



LITHIA. 



This alkali was lately discovered by M. Arfvred- 

 son, a Swedish chemist. It is found to be a con- 

 stituent of certain stones, and has been met with 

 in the petalite, spodumen, and lepidolite. Jt is of 

 the class of fixed alkalies ; is soluble in water, has 

 an acrid taste, and changes vegetable blues to 

 green. It forms neutral salts with the acids. 



Lithia, like the other fixed alkalies, has been 

 found by analysis to be the oxide of a peculiar 

 metal, which has been called Lithium. Its decom- 

 position has been effected by the voltaic pile, but 

 the quantity of metal obtained has been extremely 

 small. 



