ELISHA MITCHELL SCIENTIFIC SOCIETY. 



121 



CHART I. 



THE PRECIPITATION OF THE SOLUBLE PHOSPHORIC ACID OF A HIGH GRADE 

 ACID PHOSPHATE (CONTAINING 12.72 PER CENT. SOLUBLE PHOSPHORIC ACID) 

 DUE TO THE ACTION OF FOUR VARIETIES OF MOIST SOIL, FOR A PERIOD 

 OF 27 WEEKS. 



