G80 ANNUAL UEl'OKT OF THE Off. Doc. 



chlorid or nnirialo, the cheaper source. The comi)iitation is made 

 on the assnniption that the chh)riii ])resent, unless in excess, has 

 been introduced in tlie form of muriate of potash ; but doubtless 

 there are occasional exceptions to this rule. One part of chlorin 

 combines with 1..'526 parts of potash to form the pure muriate; know- 

 ing the chlorin, it is, therefore, easy to compute the potash equiva- 

 lent thereto. (7) In the case of ground bone, the state of sub-divi- 

 sion is determined by sifting through accurately made sieves; the 

 cost of preparation and especially the promptness of action of bone 

 in the soil depends very largely on the fineness of its particles the 

 finer being much more quickly useful to the plant. 



The preceding paragraph sets forth the nature of the examinations 

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

 prior to the present year. The legislation of 1909 has made needful, 

 however, 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, at the time of pre- 

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

 characteristic of the several materials above named. The act of 

 April 28, 1909, makes it unlawful to use the word "bone" in connec- 

 tion with, or as a 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 Avhich 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 

 ijone; 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 use- 

 ful 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 earthy fillers can legally 

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

 as "make- weights" and as "conditions," or materials introduced to 



