234 CONSERVATIVE ORGANS. [LRCT. V. 



vegetation both in young and mature plants. 

 Lime also hastens the decomposition and solution 

 of vegetable matter; and has been long known 

 as a most useful manure when applied where 

 half-decomposed vegetable matter abounds, as for 

 example, in peat soils. The best corrective, there- 

 fore, for ground that has been too much dunged 

 is lime : and peat mosses *, which consist of vege- 

 table substances, the decay of which has been sus- 

 pended by the formation of a peculiar acid in 

 them, are rendered arable and highly fertile by a 

 proper use of lime. In this operation the lime is 

 combined with the acid contained in the moss, 

 and also with carbonic acid, and remains as a 

 component of the newly-formed soil. Every kind 

 of quicklime, however, does not answer for ma- 

 nure, and particularly that which abounds with 

 magnesia; for although magnesia, when united 

 with carbonic acid, is a useful ingredient in a 

 soil, yet in its uncombined state, or as calcined 

 magnesia, which is that in which it must be, when 

 magnesian limestone is burnt into quicklime^, it is 



* Peat appears to be formed by the occasional flooding of 

 places where successive generations of vegetables have grown, 

 and been allowed to decay undisturbed, until at length the de- 

 composition is stopped by the water not passing off. The 

 soil is thus rendered spongy, and an acid is generated which 

 prevents the farther production of vegetation. 



f Magnesian limestones are easily distinguished by their 

 dissolving very slowly in acids ; and by their rendering weak 

 solutions of nitric acid turbid. 



