198 OF MANURE. 



the preparation of this useful manure states in its 

 specification, that the night-soil is to be mixed with 

 calcined mud and finely-divided charcoal. By this 

 means, the smell is completely and instantaneously 

 removed, and the ammonia retained by virtue of the 

 affinity, which alumina and charcoal exert for that 

 compound. This plan is both simple and efficacious, 

 but the ammonia is apt to be expelled by the appli- 

 cation of the heat employed in drying the manure. 

 The addition of a cheap mineral acid to the night- 

 soil, before admixture with these ingredients, would 

 materially improve both of the above processes. 



It would no doubt be highly advantageous in the 

 preparation of manures, to prepare them so that 

 they contained all the ingredients necessary for the 

 supply of the plants to which they are applied. But 

 these w^ill of course vary according to the nature of 

 the soils and plants for which they are intended. 

 Thus bones, soap-boilers' waste, nitrate of soda, 

 and ashes of wood, will often be found to form 

 advantageous additions. Sulphate of magnesia (Ep- 

 som salts) would, in most cases, form an invaluable 

 ingredient in prepared night-soil. (See Supplemen- 

 tary Chapter on Soils.) The products of the decom- 

 position proceeding from the action of this salt upon 

 night-soil are, sulphate of ammonia, phosphate of 

 magnesia, and the double phosphate of magnesia 

 and ammonia. Now all these salts exert a very 

 favorable influence upon vegetation, and the phos- 

 phate of magnesia is, in many cases, perfectly indis- 

 pensable to the growth and development of certain 

 plants. This suggestion is well worthy of the 

 attention of the farmer. 



Perhaps the best and most practical method of 

 fixing the ammoniacal salts of urine and night-soil, 

 is to mix them with the ashes of peat or coal. When 

 the latter are employed, care must be taken to select 

 such as are of a porous, earthy consistence. The 

 ashes both of peat and coal contain in general mag- 

 nesia; hence their value as an ingredient of prepared 



