APPENDIX. 59 



1. Iii the case of hydrochloric acid, the following 



chemical equation will represent the nature of the reac- 

 tion 



2HC1 + (NH 4 ) 2 C0 3 = 2NH 4 C1 + H 2 + C0 2 



(Hydrochloric (carbonate of am- (sal-ammoniac,) (carbonic acid.) 

 acid,) monia,) 



2. In the case of sulphuric acid, the equation will be 

 H 2 S0 4 + (NH 4 ) 2 C0 3 (NH 4 ) 2 S0 4 + H 2 + C0 2 



(Sulphuric (carbonate of am- (sulphate of am- (carbonic acid.) 

 acid , ) monia, ) monia, ) 



3. With cjypsum (CaS0 4 ) 



CaS0 4 + (NH 4 ) 2 C0 8 CaC0 3 + (NH 4 ) 2 S0 4 



(Gypsum,) (carbonate of ammonia,) (calcium car- (sulphate of am- 



bonate,) monia.) 



4. "With copperas (FeS0 4 ) 



FeS0 4 + (NH 4 ) 2 C0 3 FeC0 3 + (NH 4 ) 2 S0 4 



(Sulphate of (carbonate of am- (ferrous car- (sulphate of am- 

 iron,) monia,) bonate,) monia.) 



5. With sulphate of magnesia (MgS0 4 ) 



MgS0 4 + (NH 4 ) 2 C0 3 MgC0 3 + (NH 4 ) 2 S0 4 



(Sulphate of (carbonate of am- (carbonate of (sulphate of am- 

 magnesia,) monia,) magnesia,) monia.) 



Keference has been made to the fact that magnesium 

 sulphate may probably not only fix the ammonia, but the 

 phosphoric acid. When magnesium sulphate, soluble 

 phosphoric acid, and ammonia, are brought in contact 

 with one another, the double insoluble phosphate of 

 ammonium and magnesium (MgKH 4 P0 4 6Aq) is formed. 

 While such a reaction is possible, it is highly improbable 

 that it takes place to any extent. The double phosphate 

 is a crystalline salt which only separates after a con- 

 siderable time, and in the presence of a large excess of 

 ammonia. 



