No. 6. DEPARTMENT OF AGRICULTURE. 673 



soluble in water — most of that present in green sand marl and 

 crushed minerals, and even some of that present in vegetable mate- 

 rials 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, with- 

 out distinguishing between the quantities present in the several forms 

 of ammonium salts, nitrates or organic matter. (5) Chlorin — this 

 determination is made to afford a basis for estimating the proportion 

 of the potash that is present as chlorid or muriate, the cheaper source. 

 The computation is made on the assumption that the chlorin present, 

 unless in excess, has been introduced in the form of muriate of potash ; 

 but doubtless there are occasional exceptions to this rule. One part 

 of chlorin combines with 1.32G parts of potash to form the pure 

 muriate; knowing the chlorin, it is, therefore, easy to compute the 

 potash equivalent thereto. (7) In the case of ground bone, the state 

 of sub-division is determined by sifting through accurately made 

 sieves; the cost of preparation and especially the promptness of 

 action of bone in the soil depend very largely on the fitness of its 

 particles, the finer being much more quickly useful to the plant. 



The preceding praagraph sets forth the nature of the examinations 

 given to the several classes of fertilizers under the laws in force 

 prior to 1909. The legislation of 1909 has made needful, how- 

 ever, some additional tests. Sec. 4, of the Act of May 1, 1909, pro- 

 hibits the sale of "pulverized leather, hair, ground hoofs, horns, or 

 wool waste, raw, steamed, roasted, or in any form, as a fertilizer, or 

 as an ingredient of a fertilizer or manure, without an explicit state- 

 ment of the fact." All nitrogenous fertilizers have, therefore, been 

 submitted to a careful microscopic examination, .it the time of prepar- 

 ing the sample for analysis, to detect the presence of the tissues 

 characteristic of the several materials above named. The act of April 

 23, 1909, makes it unlawful to use the word "bone" in connection 

 with, or as part of the name of any fertilizer, or any brand of the 

 same, unless the phosphoric acid contained in such fertilizer shall 

 be the product of pure animal bone. All fertilizers in whose name 

 the word "bone" appears, were therefore examined by microscopic 

 and chemical methods to determine, so far as possible with present 

 knowledge, the nature of the ingredient or ingredients supplying the 

 phosphoric acid. It is a fact, however, well known to fertilizer man- 

 ufacturers and which should be equally understood by the con- 

 sumer, that it is, in certain cases, practically impossible to determine 

 the source of the phosphoric acid by an examination of the finished 

 fertilizer? The microscope shows clearly the structure of raw bone, 

 but does not make it possible to discriminate between thoroughly 

 acidulated bone and acidulated rock. The ratio of nitrogen to phos- 

 phoric acid in a raw bone — and only such bone as has not been 

 deprived of any considerable proportion of its nitrogenous material 

 by some manufacturing process can properly be called "pure animal 

 bone" — is about 1:8; in cases where the ratio of nitrogen to phos- 

 phoric acid exceeds 8, it is clear that part, at least, of the phos- 

 phoric acid has been supplied by something else than pure animal 

 bone; but, inasmuch as nitrogen may have been introduced in some 

 material other than bone and no longer detectible by the microscope, 



43—6—1911 



