pounds of bone or rock, it would be a 40% acidula- 

 tion, as 800 is 40% of 2000 pounds. 



In acidulated goods, whether rock or bone, there 

 are always three forms of phosphoric acid a soluble 

 form, a " reverted " form, and an insoluble form. The 

 last is of no commercial value. The " reverted " is of 

 doubtful value, as it has to first undergo a chemical 

 change before becoming available. The soluble is 

 immediately available. A dealer giving an analysis 

 should not mention the amount of insoluble phos- 

 phoric acid, as it is confusing. An insoluble portion 

 is necessary in order to obtain the soluble, but does 

 not add value to the fertilizer. State laws, as a rule, 

 allow the reverted to be estimated as available with 

 the water-soluble, so that the soluble and reverted 

 forms constitute the phosphoric value of a fertilizer. 



It must be remembered that in using acidulated 

 goods (bone or rock) if an abundance of lime be 

 present in the soil, the soluble form of phosphoric 

 acid unites chemically with the lime and is made 

 again insoluble as if it had never been treated. Iron, 

 and alumina, and other bases, produce the same 

 effect on acidulated phosphates. The reversion, how- 

 ever, depends on the amount of acid used by the 

 manufacturer and the quantity of lime, iron, etc., in 

 the soil. 



STEAMED BONE. 



Steaming bones removes the fats and gelatines, 

 12 



