792 ANNUAL REPORT OF THE Off. Dec. 



THK CHEMIST'S REPORT OF ANALYSES OF 

 FERTILIZERS MADE FROM AUGUST 1, TO 

 DECEMBER 31, 1901. 



Hon. John Hamilton, Secretary of Agriculture: 



During the six months ending December 31, 1901, there were re- 

 ceived from the authorized sampling agents, five hundred and nine- 

 ty-three (593) fertilizer samples, of which three hundred and eleven 

 were subjected to analysis, the remainder being rejected either be- 

 cause they represented brands analyzed last spring, 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, portions from the several samples were united 

 and the composite sample was subjected to analysis. 



The samples analj-zed group themselves as follows: One hundred 

 and seventy-nine complete fertilizers, furnishing phosphoric acid, 

 potash and nitrogen; five dissolved bones, furnishing phosphoric 

 acid and nitrogen; forty-two rock, and potash fertilizers, furnishing 

 phosphoric acid and potash; forty-nine acidulated rock phosphates, 

 furnishing phosphoric acid only; thirty -three ground bones, furnish- 

 ing phosphoric acid and nitrogen; three miscellaneous fertilizers, 

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

 stances not readily classified under the foregoing heads. 



The determinations to which a complete fertilizer is subjected are 

 as follows: (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 iuimediate 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" pliosj)horic acid. (.3) Potash soluble iu water,— most of that 

 present in green sand marl and crushed miiu'rals. and even some of 

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

 being included because insoluble in watci- even after long boiling. (4) 



