896 ANNUAL REPORT OF THE Off. Doc. 



careful study of freight rates to local centers, but the excess of 

 average selling price over average valuation is probably more than 

 increased freight rates can explain. 



FERTILIZER ANALYSES, AUGUST 1 TO DECEMBER 31, 1903. 



Since August 1, 1903, there have been received from authorized 

 sampling agents nine hundred and twenty-nine fertilizer samples, 

 of which four hundred and sixty-three 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 group themselves as follows, 264 complete fertilizers, 

 furnishing phosphoric acid, potash and nitrogen; 11 dissolved bones, 

 furnishing phosphoric acid and nitrogen; 74 rock-and-potash fer- 

 tilizers, furnishing phosphoric acid and potash; 60 acidulated rock 

 phosphates, furnishing phosphoric acid only; 49 ground bones, fur- 

 nishing phosphoric acid and nitrogen; 5 miscellaneous fertilizers, 

 which group includes potash salts, nitrate of soda and other sub 

 stances not properly classified under the foregoing heads. 



The determinations to which a complete fertilizer is subjected are 

 as follov\'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 element 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- 



