No. 6. DEPARTMENT OF AGRICULTURE. 667 



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, at 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 prosphoric 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 ration 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, 

 the presence of nitrogen and phosphoric acid in the proportions cor- 

 responding to those of bone is not proof positive that they have been 

 supplied by bone. Finally, the differences in the iron and silica con- 

 tent of bone and rock respectively, afford means of distinction useful 

 in some cases; the usefulness of this distinction is limited, how- 

 ever, by the facts that kitchen bone frequently contains earthy im- 

 purities rich in iron and silica, and that earthly fillers can legally 

 be used in fertilizers and are in fact considerably used therein both 

 as "make-weights" and as "conditioners" or materials introduced to 

 improve the drilling qualities of the goods. The fact that the phos- 

 phoric acid in bone and rock are identical in character is probably 

 so well known as to require no detailed consideration in this con- 

 nection. 



The law having required the manufacturer to guarantee the amount 

 of certain valuable ingredients present in any brand he may put 

 upon the market, chemical analysis is employed to verify the guaran- 

 ties stamped upon the fertilizer sacks. It has, therefore^ been deemed 

 desirable in this report to enter the guaranty filed by the manufac- 

 turer in the office of the Secretary of Agriculture, in such connection 

 with the analytical results that the two may be compared. An un- 

 fortunate practice has groAMi up among manufacturers of so woiding 

 the guaranty that it seems to declare the presence in the goods of an 

 amount of valuable constituent ranging from a certain minimum 

 to a much higher maximum; thus, "Potash, 2 to 4 per cent." is a 



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