OF AGRICULTURE. 235 



excrements, after being mixed with charcoal- dust 

 or charcoal peat. By these its effluvia is absorbed, 

 and when dried, it becomes a convenient fertilizer 

 for use, and will bear remote transportation. Tho 

 odor is sometimes expelled by adding quick lime, but 

 this removes with it much of the ammonia, and, on 

 this account, should be avoided. 



Urate, as well as poudrette, has become an article of 

 commerce. It is manufactured in large cities by 

 collecting the urine, and mixing with it one-sixth 

 or one- seventh of its weight of ground gypsum, 

 (sulphate of lime), and allowing it to stand several 

 days. The gypsum absorbs a portion of the 

 ammonia in the urine, after which it is dried 

 and the liquid is thrown away, Only a part of 

 the value is secured by this operation. It is some- 

 times prepared by the use of sulphuric acid (oil of 

 vitriol), which is gradually added to the urine, and 

 forms sulphate of ammonia, which is afterwards 

 evaporated to dry ness. This secures a greater 

 amount of the valuable properties of urine. 



NIGHT SOIL. 



Treatment of Night Soil. There has recently been 

 introduced into our large cities a method for deodor- 

 izing night soils, by the means of what are called 

 *' earth closets." These earth closets add greatly to 

 the sanitary condition of the cities in which they have 

 been introduced, and contribute vast quantities of 

 the richest fertilizing ingredients to agriculture : 

 that, too, in a dried, pulverized and portable form, so 

 as to be conveniently applied to the soil. 



We have not, as yet, had an opportunity of testing 



