112 



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 by 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 {Pounds in One Hundred Pounds of 

 Fertilizer) . 



Nitrogen, 4 



Soluble phosphoric acid, 8 



Reverted phosphoric acid, 4 



Insoluble phosphoric acid, 2 



Potassium oxide (as sulfate), 10 



The following table gives the average analysis of officially 

 collected fertilizers for 1899 : — 



