194 OF MANURE. 



from below, it becomes filled after a few days with 

 crystals of muriate of ammonia. The ammonia, the 

 presence of which the organs of smell amply testify, 

 combines with the muriatic acid and loses entirely 

 its volatility, and thick clouds or fumes of the salt 

 newly formed hang over the basin. In stables the 

 same may be seen. The ammonia that escapes in 

 this manner, is not only entirely lost as far as our 

 vegetation is concerned, but it works also a slow, 

 though not less certain destruction of the walls of 

 the building. For when in contact with the lime 

 of the mortar, it is converted into nitric acid, which 

 gradually dissolves the lime. The injury thus done to 

 a building by the formation of the soluble nitrates, 

 has received (in Germany) a special name sal- 

 peterfrass. 



The ammonia emitted from stables and neces- 

 saries is always in combination with carbonic acid. 

 Carbonate of ammonia and sulphate of lime 

 (gypsum) cannot be brought together at common 

 temperatures, without mutual decomposition. The 

 ammonia enters into combination with the sul- 

 phuric acid, and the carbonic acid with the lime, 

 forming compounds which are not volatile, and, 

 consequently, destitute of all smell. Now if we 

 strew the floors of our stables, from time to time, 

 with common gypsum, they will lose all their of- 

 fensive smell, and none of the ammonia which 

 forms can be lost, but will be retained in a condi- 

 tion serviceable as manure. 



