CALCULATION OF THE RELATIVE COMMERCIAL 



VALUE. 



The price of commercial fertilizers varies as does that of 

 potatoes, or any other commodity. When these flunctua- 

 tions are controlled entirely by seasonal economic factors, 

 the consumer may partially disregard them much in the 

 same manner as he disregards fluctuations in the price of 

 the sugar he buys. There are certain price differences, 

 however, which he cannot afford to disregard. For ex- 

 ample, there were eight diilferent brands of fertilizer sold 

 this year by eight different companies under the formula 

 5-8-7. The average price of the eight brands was $57.20 

 per ton. The lowest price was $45.40 per ton and the 



