271 



CHAPTER VII. 



POUDRETTE — HUMAN EXCREMENTS. 



Poudrette, nature of; small amount of the food of plants in it — Human 

 excrement, its value — Construction of the privies in the barracks at 

 Rastadt — Calcidation of the amount of com produced by the excrement 

 collected ; importance to the neighbourhood — Its effect not impaired by- 

 deodorising vriih sulphate of iron — The excrement of the inhabitants of 

 towns as manure — Its importance. 



POUDEETTE, sold as manure, should consist simply 

 of the desiccated excrements of man made into a 

 transportable form. This is not the case, however, as 

 most poudrettes contain, in reality, only a comparatively 

 small proportion of excrementitious matter. To show 

 this, it wiU suffice to point out that the poudrette of 

 Montfaucon, which is one of the best sorts, contains 

 28 per cent., that of Dresden from 43 to 56 per cent., 

 that of Frankfort above 50 per cent., of sand. No kind 

 of poudrette is ever met with in commerce containing 

 more than 3 per cent, of phosphoric acid, and the same 

 amount of ammonia. The construction of privies in 

 dwelling-houses (at least, in Germany) does not make it 

 practicable to keep out the sweepings and other rubbish 

 of the house ; besides, when emptjdng the pits, it is 

 often the practice, after taking out the fluid contents, to 

 throw into the residuary mass some sohd porous body, 

 such as brown-coal or turf-dust, to make it drier and 

 more convenient for removal. All additions of the kind, 

 of course, diminish the percentage of effective and 



