FERTILIZERS 45 



in nitrogen, as for example, 6% ammonia, X.825= 

 4.95% nitrogen, It takes 4.95% nitrogen to equal 

 6% ammonia. In figuring the value of a ton in 

 dollars and cents, if the nitrogen from blood or 

 nitrate of soda has a market value of 16 cents per 

 pound, its equivalent in ammonia is worth only 

 13M> cents per pound. Only one should be included 

 in the estimate. 



And so with the terms bone phosphate and phos- 

 phoric acid. The phosphoric acid comes from the 

 bone phosphate. For example, it takes 30% of bone 

 phosphate (sometimes called 'bone phosphate of 

 lime') to make 13.74% of phosphoric acid. When 

 both terms are employed by the manufacturer 

 the words "equal to" should be used thus: "Bone 

 phosphate of lime, 30%, equal to phosphoric acid, 

 13.74%," which means that the manufacturer used 

 600 pounds of bone phosphate or bone 30% of the 

 ton to obtain 13.74% of phosphoric acid. 



Multiply the percentage of bone phosphate by 

 .458 and the result will be the equivalent in phos- 

 phoric acid thus: 30% bone phosphate of lime 

 X. 458=13. 74% phosphoric acid. 



In estimating the value, for comparison, of a ton 

 in dollars and cents, phosphoric acid from fine bone 

 is worth about 5 1 / cents per pound, while its equiva- 

 lent in terms of bone phosphate is worth only 2^ 

 cents per pound. Only one should be included in the 

 estimate. 



Where the "soluble," the "reverted," and the 

 "insoluble," and the "total" phosphoric acid are all 

 given, it is understood that the "total" is made up 

 of the first three mentioned . 



