102 SULPHATE OF LIME. 



more so in water charged with or containing 

 carbonic acid, than in other, — it is then ab- 

 sorbed and assimilated by the plant; but it 

 also is supposed to assist materially in decom- 

 posing dry hard vegetable matter, from its great 

 attraction, when in this its caustic state, for 

 the gases combined with other substances, and 

 hence its use on peaty soils. Care should al- 

 ways be taken to procure this article as fresh 

 and as perfectly burnt as possible, and as short 

 a time as possible before it is made use of, as 

 lime when only just taken from the kiln can 

 be said to be pure, for immediately on its re- 

 moval it begins to absorb the carbonic acid gas 

 of the atmosphere, and to resume its original 

 state of a carbonate of lime. 



It has also a great affinity for nitrogen, with 

 which it readily unites to form nitrate of lime, 

 and although in this state it still produces in a 

 moderate degree the effects produced by lime, 

 its effects are not superior to chalk, which ge- 

 nerally can be obtained at a less cost. 



Sulphate of Lime, or Gypsum composed of 

 sulphuric acid and lime, the next in order and 

 in importance of the compounds of lime, oc- 

 curs native in various districts of England, the 

 most abundant quarries or pits being in Derby- 

 shire. It is found also abundantly in the 

 neighbourhood of Paris, from whence its popu- 

 lar name, "plaster of Paris," is derived. 



The beneficial results arising from the use 

 of this manure on grass lands are admitted 

 on all hands, and even in the few instances 

 where no good results have followed its use, it 



