524 ANNUAL REPORT OF THE OfE. Doc. 



or muriate, usually the cheaper source. The computation is made on 

 the assumption that the chlorin present, unless in excess, has been in- 

 troduced in the form of muriate of potash; but doubtless there are 

 occasional exceptions to this rule. One part of chlorin combines 

 with 1.326 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 fineness of its particles, the finer 

 being much more quickly useful to the plant. 



The legislation of 1909 has made needful some additional tests. 

 Section 4, of the Act of May 1, 1909, prohibits the sale of "pulverized 

 leather, hair, ground hoof, 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 statement of the fact." All 

 nitrogenous fertilizers have, therefore, been submitted to a careful 

 microscopic examination, at the time of preparing 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 phos- 

 phoric 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 manufacturers and which 

 should be equally understood by the consumer, that it is, in certain 

 cases, practically impossible to determine the source of the phos- 

 phoric acid by an examination of the finished fertilizer. The micro- 

 scope 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 phosphoric acid in a raw 

 bone — and only such a bone as has not been deprived of any consid- 

 erable 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 phosphoric acid to nitrogen exceeds 8, it 

 is clear that part, at least, of the phosphoric 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, the presence of nitrogen and 

 phosphoric acid in the proportions corresponding to those of bone is 

 not proof positive that they have been supplied by bone. Finally. 



