Chemical Analyses of Fertilizers 187 



as to the comparative agricultural value of brands of 

 the same general composition. 



CALCULATION OF COMMERCIAL VALUES 



The following examples illustrate how commercial 

 values of complete fertilizers and of ground bone are 

 calculated. The mixed, or complete, fertilizer contains 

 the three forms of nitrogen, three of phosphoric acid, 

 and the two forms of potash. In the bone, it is assumed 

 that 50 per cent of the meal is finer than 1-50 inch, and is, 

 therefore, regarded as fine, and that 50 per cent is coarser 

 than 1-50 inch, and is, therefore, regarded as coarse; 

 and it is also assumed that the proportions of the nitrogen 

 and phosphoric acid in the fine and coarse is the same; 

 also, that the analysis shows the bone to contain 4 per 

 cent of nitrogen and 20 per cent of phosphoric acid : 



A COMPLETE FERTILIZER 



1 234 



Estimated 

 Value value per 



% or Iba. Lbs. per Ib. ton of each 



per 100 pear ton eta. constituent 



Nitrogen, as nitrates ... 1 X 20 = 20 X 16.5 = $3.30 



Nitrogen, as ammonia salts 

 Nitrogen, as organic matter 

 Phosphoric acid, soluble 

 Phosphoric acid, reverted 

 Phosphoric acid, insoluble 

 Potash, as muriate . . 

 Potash, as sulphate . . 



1 X 20 = 20 X 16.5 = 3.30 



1 X 20 = 20 X 19.5 = 3.90 



8 X 20 = 160 X 4.5 = 7.20 



1 X 20 = 20 X 4.0 = .80 



1 X 20 = 20 X 2.0 = .40 



5 X 20 = 100 X 4.0 = 4.00 



5 X 20 = 100 X 5.0 = 5.00 



Total estimated value per ton $26.90 



The first column shows the percentage of the con- 

 stituents contained, which, multiplied by 20, gives the 

 pounds per ton in the second column, which, multiplied 



