294 POUDRETTE. 



season in which it is applied. It seems to have no effect oii ihe 

 crop of the succeeding year. Farm-yard dung, on the contrary, 

 only exerts a portion of the whole amount of its beneficial influence 

 in the course of the year in which it is laid on ; it has still something, 

 often much, in reserve for succeeding years. To compare liquid 

 manure with farm-yard dung, with reference to an annual crop, is to 

 compare this manure to the unknown fraction of the farm-yard dung 

 which comes into play in the course of the first year, and from such 

 a contrast no possible inference can be drawn in regard to the rela- 

 tive value of the two kinds of dung. 1 have insisted upon this cir- 

 cumstance, because it is often involved in the estimates that are 

 made of the relative values of the different species of manure ; and 

 because, from losing sight of it, unfavorable conclusions are frequently 

 come to in regard to manures that undergo decomposition very slow- 

 ly ; these manures, nevertheless, acting for a great length of time, 

 produce both a greater amount and a more durable kind of ameliora- 

 tion of the soil. Rapidity of action, in a manure, is undoubtedly a 

 quality that is highly valuable in many cases ; and Flemish manure 

 possesses this quality in the highest degree. Nevertheless, it is also 

 an advantage to possess a manure which elaborates gradually, and 

 according to the exigencies of vegetables, those principles that 

 contribute to their growth, and which suspend in a great measure 

 this elaboration in the course of the winter — which remain during 

 the cold and rainy season in an almost inert condition, when any 

 fecundating matter produced would merely be washed away and lost. 

 These advantages, to which must be added that of breaking up and 

 lightening the soil, are all possessed by good farm-yard manure. 

 They are such, in fact, that this manure, even in Flanders, is still 

 indispensable ; the liquid manures of that country are nothing more 

 than annual auxiliaries. 



The method followed in Flanders of using night-soil is certainly 

 highly rational ; it is the same as that which is adopted in Alsace, in 

 the neighborhood of towns, with this difference, that our farmers 

 collect no store of the material ; they go in quest of it at the moment 

 it is wanted. It is applied as in Flanders, or it is incorporated with 

 absorbent substances, such as straw, or with other more consistent 

 manures. The night-soil of Paris, which in the course of a year 

 amounts to an immense quantity, is treated in a totally different 

 manner, which appears to be in opposition to the simplest notions of 

 science, of economy, and of all that is conducive to health. I allude 

 to the mode of preparing poudrette. 



In the neighborhood of Paris there are places appropriated to the 

 reception of the night-soil : it is thrown into reservoirs of no great 

 depth, in comparison with their superficial extent, and of an aggre- 

 gate capacity which is such that they will contain the whole of the 

 products collected by the night-man in the course of six months. 

 These reservoirs are arranged in stages, one above another. Into 

 the upper one are discharged the matters collected in the course of 

 the night. The upper reservoir full, a slu'ce is opened by being 

 pushed partially down, which allows the ir.rre liquid matters to es- 



