180 Fertilizers 



may, too, be fairly indicated, and will vary according to 

 variations in trade conditions. If the wholesale jobbing 

 price of nitrogen as nitrate is 15 cents a pound, available 

 phosphoric acid 5 cents a pound, and potash 4 cents a 

 pound, these are the prices which the manufacturers pay. 

 Their increased cost in manufactured brands, therefore, 

 is in proportion to the cost of this work ; hence their cost 

 to the consumer at factory should vary within reasonably 

 narrow limits, due to variations in cost of manufacturing 

 in different localities. 



An illustration of the commercial value is shown by 

 the following example : Suppose that nitrate of soda costs, 

 or can be purchased at retail, in ton lots, for $48 a ton, 

 which is, then, its commercial value. The commercial 

 or trade value of the nitrogen is, therefore, 15 cents a 

 pound, since a ton contains on the average 320 pounds 

 of nitrogen. Or, suppose that the retail price of avail- 

 able phosphoric acid in superphosphates is $1 a unit; 

 this is its commercial value, and hence the commercial or 

 trade value of the available phosphoric acid would be 5 

 cents a pound, since a unit contains 20 pounds. It does 

 not follow that the application of a pound of nitrogen 

 costing 15 cents, and therefore having a commercial 

 value of 15 cents, will result in an increased crop worth 

 15 cents, or that the application of a pound of phosphoric 

 acid costing 5 cents a pound will result in an increased 

 crop worth 5 cents. The increased returns in crop from 

 their use may be very much greater or much less than the 

 cost of the constituents, depending upon the kind of crop 

 and the skill of the user. In the purchase of materials, 

 however, a commercial valuation is a guide as to the cost 

 of the constituents from different manufacturers or dealers ; 

 and in many states a system of commercial values for 



