38 



ELEMENTS OP 



salts, uric acid, (a substance itself containing much ni- 

 trogen,) and salts of phosplioric acid. 

 Human urine consists, in 1000 parts, of 



Water .932 



Urea, and other organic matters contain- ^ ^q 



ing nitrogen . . . . ) 



Phospliates of ammonia, soda, lime, and ) n 



magnesia ( 



Sulphates of soda and ammonia . . 7 



Sal ammoniac and common salt . 6 



1000 



In manure reservoirs, well constructed and protected 

 frpm evaporation, tlie carbonate of ammonia, which 

 forms in consequence of putrefaction, is retained in so- 

 lution ; and when the putrified urine is spread over the 

 land, a part of ibis ammonia will escape with the water 

 which evaporates. On account of the formation of car- 

 bonate of ammonia in putnd urine, it becomes alkaUne, 

 thuugh naturall}' acid m its recent state ; and when ihis 

 carbonate of ammonia is lost by being volatilized in the 

 air, (which happens in mo.-t cases,) the loss sufTtired is 

 nearly equal to one-half of the uiine employed. So 

 that, if we fix the anmionia, (by combining it with some 

 acid which forms with it a compound not volatile,) we 

 increase its action two-fold. Now the carbonate of 

 amnjonia formed by the putrefaciion of urine, can be 

 fixed, or deprived ol its volatility, in many ways. 



If, for instance, a field be strewed with gypsum, or 

 plaster of Paris, (in clieinir-al langnnge, sulplfaie of lime.) 

 and thf^n spiitikietl with urine, or the drainiiigs uf the 

 cow-shed, a douMe exchange or (lccom| o-iiio:i takes 

 place. I^ul[)hate of lime and carl)onatti of ammonia 

 become convicted into carbonate of lime, (that is, chalk,) 

 and sulphate of ammonia ; and this b.'caiise sulphuric 

 acid has a great.^- atlinity for ammonia than it has for 

 lime. This sulphate of ammonia will remain in the 

 soil — it will not evaporate. 



If a basin containing spirit of jalt, or muriatic acid, 



