12 



Nitrogen : Cents 



per lb. 

 Nitrogen in salts of ammonia or in nitrates, as 



well as in compound fertilizers 17 



Organic nitrogen in ground bone, fish, blood or 



tankage 16 



Phosphoric acid : 



Soluble in water 6 



Soluble in 1 per cent, citric acid solution 5^ 



Insoluble as in Thomas ' phosphate powder 3^ 



Insoluble as in ground rock phosphate and fertiliz- 

 ers generally 1^ 



Potash : 



Potash in high-grade salts 5 



The value of these figures is that by their use and the percentage 

 composition, or guarantee, the purchaser is able to calculate, at least, 

 the approximate cost of the fertilizer and is thus not likely to be imposed 

 upon. Voorhees, in his book on "Fertilizers," points out that there is 

 a very decided lack of intelligent application of this information, and 

 gives the following illustration of the fact that farmers do, in many cases, 

 pay exorbitant prices for their fertilizer constituents, not because the 

 manufacturer did not sell what he claimed to sell, but because the price 

 charged by the dealer was far in excess of that warranted by the guaran- 

 tee : "Two brands are offered, made up from the same kind and quality 

 of materials. No. 1 is guaranteed to contain : 



Nitrogen 1 per cent. 



Phosphoric acid (available) 6 



Potash ". .' 1 



and sells for $20 per ton ; No. 2 is guaranteed to contain : 



Nitrogen 4 per cent. 



Phosphoric acid (available) 8 



Potash 2 



and sells for $22 per ton. The farmer who buys on the ton basis, or is 

 guided only by the ton price, will be induced to purchase the No. 1 brand, 

 because by so doing he apparently saves $2 per ton. The one who studies 

 the relation of guarantee to selling price will purchase the No. 2 brand, 

 because he finds, from a simple calculation, that it furnishes the con- 

 stituents at just one-half the cost per pound of the No. 1 brand, notwith- 

 standing the higher ton price, which is shown by the following calcula- 

 tion : 



