AGRICULTURAL EXPERIMENT STATION. 33 



some particular brand shows that inferior material like leather has 

 been used. Organic nitrogen in mixed goods is therefore valued 

 at sixteen and one-half cents per pound. The nitrogen pres- 

 ent in nitrates and ammonia salts is reckoned at 16 cents and 

 17^ cents respectively. 



The insoluble phosphoric acid of mixed fertilizers is considered 

 as coming entirely from bone, and not from South Carolina rock , 

 and is reckoned at three cents per pound. 



The potash is valued at the price of that ingredient in kainite and 

 the muriate, unless the chlorine present in the fertilizer is not 

 sufficient to combine with it, in which case the excess of potash is 

 reckoned as the sulphate. 



The valuation of a fertilizer is obtained by multiplying the per- 

 centages of the several ingredients by twenty (which gives the 

 pounds per ton), and these products by the prices per pound, and 

 the sum of the several final products is the market value of the 

 fertilizing ingredients in one ton. 



These estimated values should be studied in the light of the pre- 

 vious explanations. It will probably rarely happen in this State 

 that a mixed fertilizer can be sold near the point of consumption as 

 low as the Station valuation, the excess of cost representing cer- 

 tain expenses previously enumerated. The station valuations give 

 the consumer a fairly accurate basis for estimating the relative cost 

 of plant-food in the various brands of fertilizers, and will help the 

 farmer to determine whether he can in any way profitably change 

 bis methods of buying fertilizing ingredients. A caution should be 

 uttered, however, against making too close an application of the 

 Station valuations, as a difference of a few cents, or even of a dol- 

 lar, on a ton between two brands may have no real significance, but 

 may be due to unavoidable errors of sampling and analysis, that 

 render it impossible to determine to the utmost exactness the com- 

 position of the entire bulk of material that is sold. 



On the other hand farmers should be cautioned against the state- 

 ments of interested parties to the effect that the Station valuations 

 are misleading and are worthless as a guide to the farmer. It is 

 generally accepted that nitrogen, phosphoric acid and potash are 

 the ingredients which determine not only the agricultural, but also 

 the commercial value of a fertilizer. The most searching tests of 

 the chemical methods now in use by official chemists show that these 



3 



