190 AMERICAN MANURES. 



When it sets in, the heat gradually increases 

 until it has reached a certain point; then it 

 decreases, until it is imperceptible. The pile 

 should then be shovelled over, and a second fer- 

 mentation will take place as before ; this cooling 

 of the pile being caused by the exhaustion of 

 available oxygen in the mass. If the farmer 

 has attended to applying gypsum as directed, 

 there will be no loss or damage produced by 

 overheating. 



A great deal of vapor is formed during the 

 fermentation, and a part of it escapes into the 

 atmosphere. The farmer should be careful to 

 note whether it contains any ammonia, which 

 he can do by the smell. If it does, a light 

 sprinkle of gypsum, with a little dry earth, will 

 prevent loss. Part of the vapor condenses as it 

 approaches the surface of the heap, and will 

 gradually find its way into the drain ; and as it 

 flows out, it can be mixed with earth or muck, 

 and a little plaster, and thrown on the heap. 



One great mistake commonly made by our 

 farmers, is in not allowing the compost heap a 

 sufficient time to become thoroughly decomposed, 

 before applying it. The time required to effect 

 complete decomposition is from one to two years ; 

 and should it be used before decomposition is 

 completely accomplished, the farmer does not 

 get that return for his labor in collecting, mix- 

 ing, and turning over, that lie would realize if 



