AGRICULTURE WITH CHEMISTRY. 209 



formed by the combination of the magnesian earth 

 with the oxalic acid, will, as well as the vegetable matter 

 dissolved by the alkali, be found to promote vegetation 

 in a very great degree; hence magnesia, by forming 

 with the oxalic acid a soluble salt, has an advantage 

 over lime, which forms with the same acid a salt that is 

 nearly insoluble, but capable of being brought into action 

 by methods previously stated. 



By the application of alkaline salts to sorel, there re*- 

 suits a salt fully neutralized, which highly promotes 

 the vegetation or growth of more valuable plants and 

 grain. 



When neither magnesia nor alkaline salts are to be 

 procured, and where it is not thought proper to make 

 use of lime, the thinly paring and burning the sward, 

 consisting of the plants of sorel and their roots, may be 

 performed with advantage, as a large proportion of al- 

 kaline salts will be procured for the purpose of dissolv- 

 ing a correspondent proportion of the inert vegetable 

 matter contained in the soil. This operation of paring 

 and burning is only recommended as a last resource, 



D d and 



