185 



Now the oxide of zinc from the sulphate being redissolved 

 by potash, there must be formed the similar compound 



K.O.SO3 + ZWO.KO. 



This cannot be obtained crystallized, for if the liquor be 

 evaporated there is deposited K0.SO3, and zno.KO remains dis- 

 solved ; from this, by exposure to the air, there are gradually 

 deposited, small crystals, which Dr. Kane considers as being 



K0.CO2 + zn 0.CO2 4- 2 HO. 



but by heat there is carbonic acid given off, and a powder 

 insoluble in water is produced, the composition of which, 

 from Dr. Kane's examination, appears to be 



KO.CO2 4- ZWO.CO2 + 2 zwo. 

 It will be recollected, that the bicarbonate of potash is 



KO.CO2 4- H0.C02. 

 By treating the ammonia sulphate No. 3 or 5 by water, 

 there is obtained a basic sulphate, having the formula 



ZWO.SO3 4- 6 zno 4-12 HO. 



which, dried and exposed to the air, slakes, and gives 



ZWO.SO3 -h 6 zno 4- 3 HO. 



This new salt has some remarkable relations to those already 

 known. 



There are two ammonia chlorides of zinc. 



No. 1, in pearly scales of a talcy lustre, consists of 



z«c/4- 2 NH3 4- HO, 

 and, when heated, gives off NH3.H0. leaving NH3.ZW c^. a white 

 powder. 



No. 2 is in fine quadrangular prisms, brilliant lustre, con- 

 sisting of 2 zw c^ 4- 2 NH3 4- HO. or, as Dr. Kane considers, 

 zn.cl 4- (NH3.HCQ 4- NH3.ZW0. which losing NH3.H0 leaves 

 zwc/ 4~ NHs.z^icA a white mass, fusible, congealing into a 

 mass like gum, and volatilizable. This gummy mass is like- 

 wise obtained by heating NH3ZW c/. 



