No. 7. DEPARTMENT OF AGRICULTURE. 761 



The schedule of vahiatiou adopted for use this year has given 

 valuations which agree fairly well with the average selling prices. 

 The most striking apparent deficiency is that in dissolved bone goods. 

 In this case, however, only two samples were included in the aver- 

 ages, making these figures of doubtful value for comparison. 



The true relation between valuation and selling price can be as- 

 certained only by taking into account the average freight to points 

 of sale from which sanix)les were taken this season. 



FERTILIZER ANALYSES, AUGUST 1 TO DECEMBER 31, 1904. 



Since August 1, 1904, there have been received from authorized 

 sampling agents eight hundred and twenty-six fertilizer samjjles, 

 of which four hundred and fifteen were subjected to analysis, the 

 remainder being rejected either because they represented brands 

 analyzed last season, or because they were regarded as not certainly 

 representative of the brand whose name they bore. When two or 

 more samples representing the same brand were received, equal 

 portions from the several samples were united and the composite 

 sample was subjected to analysis. 



The samples analj'zed group themselves as follows: 256 complete 

 fertilizers, furnishing phosphoric acid, potash and nitrogen; 6 dis- 

 solved bones, furnishing phosphoric acid and nitrogen; 68 rock-and- 

 Ijotash fertilizers, furnishing phosphoric acid and potash; 45 acidu- 

 lated rock phosphates, furnishing phosphoric acid only; 38 ground 

 bones, furnishing phosphoric acid and nitrogen and 2 miscellaneous 

 samples which group includes substances not properly classified 

 under the foregoing heads. 



The determinations to which a complete fertilizer is subjected are 

 as follow^s: (1) Moisture, useful for the comparison of analyses, for 

 indication of dry condition and fitness for drilling, and also of the 

 conditions under which the fertilizer was kept in the warehouse. (2) 

 Phosphoric acid total, that portion soluble in water, and of the 

 residue, that portion^ not soluble in warm ammonium citrate solution 

 (a solution supposed to represent the action of plant roots upon 

 the fertilizer), which is assumed to have little immediate food value. 

 By difference, it is easy to compute the so-called ''reverted" acid, 

 which is the portion insoluble in water but soluble in the citrate. 

 The sum of the soluble and reverted is commonly called the "avail- 

 able" phosphoric acid. (3 Potash soluble in water, — most of that 

 present in green sand marl and crushed minerals, and even some of 

 that present in vegetable materials such as cotton-seed meal, not 

 being included because insoluble in water even after long boiling. 

 (4) Nitrogen — this elewient is determined by a method which simply 

 accounts for all present, without distinguishing between the quanti- 

 ties present in the several forms of ammonium salts, nitrates or or- 

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