FERTILIZERS. 39 



these are distinctly manufacturing processes that do require 

 technical knowledge, skill in manipulation and expensive ma- 

 chinery. But these operations are entirely separate and distinct 

 from the compounding of mixed fertilizers. Each of the ma- 

 terials named comes from the manufacturer in condition to be 

 used by itself as a fertilizer, and each is so used for special 

 purposes. But the compounding, or putting together of these 

 materials in different proportions into a mixed fertilizer is no 

 more a manufacture than is mixing together a ration of bran 

 and cornmeal for a cow. The only difference is that a ration 

 which is designed to be distributed uniformly to thousands or 

 millions of plants requires to be more carefully mixed than 

 that fed to a single cow. If each plant were being fed in- 

 dividually, or if each element in a fertilizer were being applied at 

 different times, as for instance, when we apply acid phosphate 

 and muriate of potash to wheat in the fall, and nitrate of soda 

 in the spring, no mixing would be necessary. 



"This point of the essential difference between those opera- 

 tions which are legitimately called 'manufacturing' and those 

 which are simply mixing, should be clearly understood."* 



Let the farmer who desires to do his own mixing decide on 

 the grade of fertilizer he desires to use, that is, the percentage 

 of ammonia, phosphoric acid and potash that the fertilizer shall 

 contain, and on the fertilizing materials that he wants to use 

 as carriers or sources of these compounds, and the proposition 

 becomes a simple problem in percentage. 



In the following table are given the composition of raw 

 materials which is here used for the purpose of illustrating the 

 method of calculating a fertilizer formula : 



Phos. 

 Ammonia. Acid. Potash. 



% % % 



Steamed bone meal 2 28 



Acid phosphate 14 



Muriate of potash . . 50 



Nitrate of soda.. 19 



*Bull. 93, Ohio Exp. Sta. 



