AGRICULTURE WITH CHEiMISTRY. 57 



the insoluble matter accumulated in soils, by the combi- 

 nation of the phosphoric and soreline acids with calcare- 

 ous matter. The vitriolic acid will join with the calca- 

 reous matter, and form gypsum ; Avhilst the posphoric 

 and soreline acids, in consequence of their disengage- 

 ment, will combine with other matters in the soil, par- 

 ticularly with magnesia, forming salts which are very 

 soluble, and conducive to the growth of plants. 



But the endless series of processes adopted by nature, 

 do not finish here; for, on a supposition, that the phos- 

 phoric and soreline acids had been fully disengaged from 

 the calcareous matter, with which they had formerly 

 been united, and that in the state of phosphat, and oxalat 

 of potash, soda, ammoniac, or magnesia, they had expend- 

 ed themselves in the process of vegetation; still the gyp- 

 sum remaining in the soil would, on a renewed applica- 

 tion of dung, animal or vegetable matter, be brought 

 from the state of gypsum, which is insoluble, to a state 

 approaching to that of a hepar of lime, which is solu- 

 l)le ; and as the vitriolic acid and calcareous matter are con- 

 tained in, and form a part of the compounded residuum 



H of 



