58 



HATCH EXPERIMENT STATION. 



[Jan. 



How to use the table of trade values in calculating the ap- 

 proximate value of a fertilizer : Calculate the value of each 

 of the three essential articles of plant food (nitrogen, phos- 

 phoric acid and potassium oxide, including the different 

 forms of each wherever different forms are recognized in the 

 table) in one hundred pounds of the fertilizer, and multiply 

 each product hy twenty, to raise it to a ton basis. The sum 

 of these values will give the total value of the fertilizer per 

 ton at the principal places of distribution. An example will 

 suffice to show how this calculation is made : — 



Analysis of Fertilizer {Per Oent., or Pounds in One Hundred 

 Pounds of Fertilizer) . 



Nitrogen, 4 



Solul)le pliosplioric acid, 8 



Reverted phosphoric acid, 4 



Insohible phosphoric acid, 2 



Potassium oxide (as sulfate), 10 



The following taljle gives the average analysis of officially 

 collected fertilizers for 1900 : — 



