DRAININGS. 113 



paste is produced ; the strong, pungent odor which 

 arises from this paste, as also the fact that a strip of 

 red test-paper held over it becomes blue, will plainly 

 enough demonstrate its presence. Lime is brought 

 into contact, in its action, with sulphuric acid ; it is a 

 stronger basis than ammonia, and for this reason takes 

 the sulphuric acid away from the latter, whereby the 

 ammonia, set at freedom, becomes aeriform and es- 

 capes. Since, therefore, lime expels ammonia from 

 the combinations it has formed, and this is then vola- 

 tilized, it is obvious that putrid drainings, like rotten 

 or completely fermented manures in general, should 

 not be mixed with lime, whether soluble or not, unless 

 their manuring power is sought to be considerably 

 weakened. The volatilized ammonia is not indeed 

 lost, but benefits the world ; inasmuch as it is diffused 

 in the air, and from this is again restored to the earth 

 by rain, snow, or dew. A rational farmer will not, 

 however, wish to be in this way a communist, but 

 will rather seek to preserve the strength of his ma- 

 nure for his own fields alone. 



The action of lime differs when mixed with fresh 

 urine, or fresh, unfermented manure, in which no 

 ready-formed combinations of ammonia, but only 

 the materials for the same, are as yet contained. In 

 this case the process of putrefaction is prevented by 

 the lime, so that nitric acid, instead of ammonia, is 

 generated from the nitrogen of the manure, which 

 subsequently combines with part of the lime to form 

 a salt, that is, nitrate of lime. Nitric acid is com- 

 10* 



