AGRICULTURE WITH CHEMISTRY. 29 



The insoluble matters consist of phosphoric, sordine, 

 or vegetable acid, combined mth lime, or calcareous 

 matter. 



These last mentioned substances may likewise be pro- 

 duced from vegetabld% which have not undergone the 

 putrefactive process, by the tendency which pure air, 

 vital air, or oxygen, has to combine with such like, and 

 all other inflammable substances ; a process here called 



OXYGENATION. 



By the combination of pure air with inflammable sub- 

 stances, particular acids are formed, with the peculiar 

 bases of those acids contained in inflammable substances. 

 The acids, as they are formed, combine either with the 

 calcareous matter of the vegetables, or with other cal- 

 careous matter in the soil, forming salts, which for the 

 most part are very insoluble. 



The process of putrefaction is always accompanied by 

 that of oxygenation : but oxygenation may be, and is to 

 a great extent, independent of put refusion. 



To 



