OF POTASH. 53 



ammoniacal salts are destitute of water of 'crystal- 

 lization, and that the hydrous salts usually con- 

 tain only 1 or 2 atoms, and very rarely more 

 than C 2 atoms of water in an integrant particle of 

 the salt. Acetate of ammonia, alone, was found 

 to contain 7 atoms, and binoxalate of ammonia 

 8 atoms. 



2. SALTS OF POTASH. 



J . Sulphate of potash. This well known salt Sulphate, 

 contains no water, but is composed of 



1 atom sulphuric acid 5 



1 atom potash . . 6 



11 



2. Bisulphate of potash. This salt, which has Bi 

 been long well known, may be easily obtained by 

 dissolving sulphate of potash in dilute sulphuric 

 acid, and evaporating the solution. It crystal- 

 lizes in thin rhomboids : the plane angles of the 

 larger faces are 97 20' and 82 40' ; and the in- 

 clinations of the faces to each other are 107 15' 

 and 72 45'. Its taste is acid and bitter, and it 

 is not altered by exposure to the air. A pretty 

 strong heat is necessary to drive off the excess of 

 acid and reduce the salt to the state of. simple 

 sulphate of potash. The proportion of the acid 

 and potasli to each other, in this salt, has been 



16 



