Chemical Analyses of Fertilizers 181 



mixed fertilizers has been fixed, which, when properly 

 understood, is a useful method of comparison of the 

 different brands. 



This method is based upon the fact that at points 

 of supply a pound of nitrogen, in the form of nitrate, 

 of ammonia or of definite organic compounds, or a 

 pound of available phosphoric acid, or of potash in the 

 form of muriate or sulfate, is practically the same to all 

 manufacturers. That is, these cost prices, or trade values, 

 when applied to the constituents in the mixture, represent 

 their commercial value before they are mixed to form 

 complete fertilizers. Hence, the difference between the 

 valuation of a brand on this basis and the cost to the con- 

 sumer represents the charges, including profit, for mixing, 

 bagging, shipping and selling the goods. 



The commercial or trade value for each of these con- 

 stituents is obtained, as already indicated, by simply 

 calculating the cost, using two factors, the wholesale 

 prices for the different materials containing them, and 

 their average composition. To this cost is added a cer- 

 tain percentage, to represent the cost of handling and dis- 

 tribution in small lots. Thus the trade value corresponds 

 as nearly as may be with the cost of the constituents to 

 the farmer. That is, the price fixed represents what the 

 farmer would have to pay the manufacturer for the con- 

 stituents in the material before it is mixed. 



For example, suppose the wholesale price a ton of 

 nitrate of soda for the six months preceding March 1 is 

 shown to be $40 ; the wholesale cost of nitrogen in this 

 form is, therefore, 12.5 cents a pound. To this wholesale 

 price may be added a certain sum to cover the expenses 

 of handling, usually 20 per cent, thus making the retail 

 price a ton $48, and the trade or commercial value of the 



