EXPERIMENT STATION. 707 



merit. The use of the highest trade vahies is leased on the 

 opinion that tliese articles ought to contain the most efficient 

 forms of fertilizing ingredients. In most cases the vahiation 

 of the ingredients in superpliosphates and specials falls be- 

 low the retail price of these goods. The difference between 

 the two figures represents the manufacturers' charges for 

 converting raw materials into manufactured articles. These 

 charijes are for g-rindino- and mixino;, baijo-incr or barrelinof, 

 storage and transportation, commission to agents and dealers, 

 long credits, interest on investment, bad debts, and, finally, 

 profits. 



Local disadvantages for transportation exert, not infre- 

 quently, a serious influence on the cost of one and the same 

 brand of fertilizers. Binding rules cannot be laid down re- 

 garding these points. Farmers must judge for themselves 

 whether the difference between our valuation and the prices 

 asked for is a fair one, considering local conditions of 

 supply. 



The prices stated in these bulletins, in connection with 

 analyses of commercial fertilizers, refer to their cost per ton 

 of 2,000 pounds on board of car or boat near the factory, 

 or place of general distribution. To obtain the valuation of 

 a fertilizer (^. e., the money worth of its fertilizing constit- 

 uents), we multiply the pounds per ton of nitrogen, etc., 

 by the trade value per pound. We thus get the values per 

 ton of the several ingredients, and, adding them together, we 

 get the total valuation per ton. 



The mechanical condition of any fertilizing material, 

 simple or compound, deserves the most serious consideration 

 of fanners, when articles of a similar chemical character are 

 offered for their choice. The degree of pulverization con- 

 trols, almost w^ithout exception, under similar conditions, 

 the rate of solubility, and the more or less rapid diffusion of 

 the different articles of plant food throughout the soil. 



The state of moisture exerts a no less important influence 

 on the pecuniary value, in case of one and the same kind of 

 substance. Two samples of fish fertilizer, although equally 

 pure, may differ from fifty to one hundred per cent, in com- 

 mercial value, on account of mere difference in moisture. 



Crude stock for the manufacture of fertilizers, and refuse 



