142 URINE. 



action, whether they are brought on a field dis- 

 solved in water or urine." Hence the power- 

 ful influence of urine must consist in its ammo- 

 niacal salts. Now, when urine is allowed 

 spontaneously to putrefy, one portion of the 

 ammonia unites with the lactic acid to form 

 lactate of ammonia, and another becomes vola- 

 tile in the state of carbonate of ammonia. 



The formation of this carbonate of ammonia 

 entirely alters the state of the urine, rendering 

 it an alkali, instead of an acid, which it is in 

 its natural state, and this explains why putre- 

 fied urine is to be preferred as a manure to 

 urine in its fresh state. Now the great object 

 is to fix this carbonate of ammonia, or at all 

 events the ammonia, in the soil. 



If the urine is applied as a manure in this 

 state, that is, with the lactate and carbonate of 

 ammonia in solution, the latter salt, from being 

 volatile, will evaporate with the watery parts 

 of the fluid ; and the loss which would accrue 

 from this mode of using it, would amount to 

 nearly ono half of the weight of the urine em- 

 ployed. So that, if by any means we can fix 

 the ammonia, that is, deprive it of its power to 

 fly off" with the evaporation of the watery parts 

 of the urine, we shall increase its action two- 

 fold. This object may be effected in a variety 

 of ways. If a field is strewed with fresh burnt 

 gypsum (sulphate of lime) and then the putre- 

 fied urine be applied on its surface, the gypsum 

 will absorb and decompose the carbonate of 

 ammonia, and the carbonic acid gas thus dis- 

 engaged, will unite with the lime to |brm car- 

 bonate of lime, and the sulphuric acid of the 



