100 MANURES. 



Another objection to its exposnre to the weather 

 is its liability to be washed away by rains. It 

 ehould be at least ten days old before being used, 

 and would be improved by an age of three or four 

 months, as the chemical changes it undergoes will 

 require some time to be completed. 



The" character of this mixture is not very clearly 

 understood. Its principal constituents are lime, 

 carbonic acid, chlorine, and soda. The salt is 

 undoubtedly decomposed in part or entirely, and 

 various compounds, containing the above substances 

 in dift'erent proportions and in diflterent forms of 

 combination, are formed. Probably the extent of 

 the decomposition of the salt aiid the character of the 

 new combinations depend on various circumstances, 

 and vary considerably. 



These compounds are much better agents in the 

 composition of muck than pure salt and lime. 



When shell lime cannot be obtained, Thomaston, 

 or any other very pure lime, will answer ; but care 

 must be taken that it do not contain much magnesia. 



LIME. 



Muck may be decomposed by the aid of other 

 materials. Lime is very efficient, though not so 

 much so as when combined with salt. The action of 

 lime, when applied to the muck, depends very nuch 

 on its condition. Air-slaked lime (carbonate of lime) 

 has less effect than hydrate of lime (lime simply slaked 

 with water), because it is less caustic in its character. 



