134 GAS LIQUOR. 



monia combined with sulphuric acid. In this 

 state the salt has entirely lost its volatile pro- 

 perties, whilst it retains its solubility, and is 

 equally, if not more, fertilizing in its effects. 



To convert this carbonate of ammonia, it is 

 only necessary to add a sufficient quantity of 

 sulphuric acid to the ammoniacal liquor, until 

 all the effervescence caused by the acid has 

 ceased. When this is effected, the carbonic 

 acid gas has passed off, and the residue is an 

 impure sulphate of ammonia. Or it may be 

 made by mixing gypsum with the gas liquor, 

 and allowing it to remain a few hours to decom- 

 pose. 



In its operation on plants, the sulphate of 

 ammonia, when applied to the land, is dissolved 

 by the first moisture, and carried into the soil, 

 where it is absorbed by the roots of the plants ; 

 the ammonia is then decomposed, and the ni 

 trogen it contains is assimilated in the way we 

 have previously described (p. 62.) 



It may be objected that this mode of pro- 

 ceeding is too expensive for general use ; but 

 as the sulphuric acid is one of the cheapest 

 acids that exists ; and as a pound (costing from 

 2d to 2d) of it will convert the carbonate con- 

 tained in three gallons of gas liquor into a sul- 

 phate, and thereby furnish 30 oz. or nearly 

 2 lbs., of sulphate of ammonia, we think, in- 

 deed we feel assured, that the additional quan- 

 tity of ammonia thus fixed in the soil would 

 amply repay the outlay. 



If the gas liquor is applied in its natural 

 state, a portion certainly of the carbonate of 

 ammonia it contains is absorbed by the earth ; 



