190 OF MANURE. 



too minute. But that contained in the faeces of 

 man is proportionably much greater, although by 

 no means constant. In the faeces of the inhabitants 

 of towns, for example, who feed on animal matter, 

 there is much more of this constituent than in 

 those of peasants, or of such people as reside in the 

 country. The faeces of those who live principally 

 on bread and potatoes are similar in composition 

 and properties to those of animals. 



All excrements have in this respect a very variable 

 and relative value. Thus, those of black cattle and 

 horses, are of great use on soils consisting of lime 

 and sand, which contain no silicate of potash and 

 phosphates, whilst their value is much less when 

 applied to soils formed of argillaceous earth, basalt, 

 granite, porphyry, clinkstone, and even mountain- 

 limestone, because all these contain potash in con- 

 siderable quantity. In such soils human excrements 

 are extremely beneficial, and increase their fertility 

 in a remarkable degree ; they are, of course, as 

 advantageous for other soils also ; but for the 

 manure of those first mentioned, the excrements of 

 other animals are quite indispensable. 



We possess only one other source of manure 

 which acts by its nitrogen, besides the faeces of 

 animals, namely, the urine of man and animals. 



Urine is employed as manure either in the liquid 

 state, or with the faeces which are impregnated with 

 it. It is the urine contained in them which gives 

 to the solid faeces the property of emitting ammonia, 



