258 SUPEKPHOSPHATE OF LIME. 



72 + 28 



form 100 lbs. superphosphates. 



78 + 78 

 form 156 lbs. plaster. 



If to the 100 lbs. of superphosphate thus obtained, 50 lbs. 

 of O. V. are added to combine with the lime, the result will 

 be as follows : 



100 lbs. superphosphate ; deduct -J- unacted on, 

 33 



67 lbs. superphosphate, containing 48.24 lbs. phos. acid, 

 and 18.76 lbs. lime. 



f of the lime, or 14.07 lbs. unite with 25 lbs. of O. V., 

 and form 39 lbs. of plaster, while 25 lbs. of O. V. remain 

 free. Of the lime, ^ or 4.69 lbs. unite with 12.06 lbs. of 

 the phosphoric acid, and form 16.75 lbs. of superphosphate, 

 while the balance of the phosphoric acid, or 36.18 lbs., dis- 

 solves the 33 lbs. of superphosphate, which were unacted on, 

 and form 69.18 lbs. of double superphosphate, or 2 acid to 

 1 lime. 



Omitting fractions, the final result of adding to 156 pounds 

 of pure bone earth, 150 pounds of O. V. will be the produc- 

 tion of 



195 lbs. of plaster of Paris, 

 25 lbs. of free oil of vitriol, 



86 lbs. of bi, or double superphosphate of lime, contain- 

 ing 72 lbs. phosphoric acid, 14 lbs. of lime. 



Thus we have all the phosphoric acid of the original 156 

 lbs. of bone earth, with i only of its lime, in this superphos- 

 phate. It is to be observed that oil of vitriol of commerce 

 contains about 40 lbs. of real acid in 50 lbs., the balance is 

 water, which enters into the composition of the plaster. 



