^1 



the farmer when purchasing a fertilizer to have some system of calculation whereby 

 he may be able to tell whether that fertilizer is selling at a price according to 

 its true market value, or not. In other words, he should know if he is getting 

 his money's worth according to the trade value. In the case of purely mineral 

 fertilizers it is evident from previous reading that the value depends upon the 

 amount and condition of the nitrogen, phosphoric acid and potash present. Now, 

 if we consider a simple mineral fertilizer like nitrate of soda, which we buy 

 only for the nitrogen it contains, it is readily seen that according to the market 

 price of this mineral we can fix a ''unit value" for nitrogen. Any unit may be 

 adopted, but the unit most conveniently adopted in the trade is stated as being one 

 per cent, on the basis of a 'ton, or 20 pounds. Thus, if nitrate of soda containing 

 15 per cent, of nitrogen is selling at $55.00 per ton, the price of a unit of nitrogen 

 is found by dividing $55.00 by 15 per cent. =$3. 66 per unit. 



Similarly, superphosphate selling at $16.00 per ton and containing 16 per cent, 

 available phosphoric acid gives the price for a unit of available phosphoric acid 

 at *i«^o<i =$1.00 per unit. 



Again, muriate of potash selling at $41.80 per ton and containing 48 per cent, 

 potash gives the price for a unit of potash at **-ij|-<'-=87c. per imit. 



According to these calculations we have the following unit values: 



Nitiogen $3.66 per unit. 



Available phosplioric acid 1.00 " " 



Potash 87 " 



Knowing a value for each of these units we can now readily estimate from 

 the guaranteed analysis which accompanies a fertilizer whether it is being offered 

 for sale at a legitimate price, or not. 



Two potato manures of the following composition, respectively, are placed on 

 the market at the prices mentioned, and it is required to ascertain which is 

 better value. 



No. I. 



Price $32.00 per ton. 



Analysis : Nitrogen :'. ... 4 per cent. 



Available phosplioric acid 8 " " 



Potash 10 " " 



No. II. 



Price $30.00 per ton. 



Analysis : Nitrogen 2 per cent. 



Available phosphoric acid 6 " " 



Potash 12 " 



, From the above unit values the value of these two fertilizers would be 

 estimated as follows: 



I. Nitrogen 4 per cent., or 4 units, at $3.66 = $14.64 



Available phosphoric acid .. 8 " " "8 " " 1.00 = 8.00 

 Potash 10 " " "10 " " .87= 8.70 



Actual value per ton = $31.34 



Price charged per ton := 32.00 



II, Nitrogen 2 per cent., or 2 units, at $3.66 = $7.32 



Available phosphoric acid .. 6 " " "6 " " 1.00= 6.00 

 Potash 12 " " "12 " " .87= 10.44 



Actual value per ton = $23.76 



Price charged per ton = 30.00 



