No. 7. DEPARTMENT OF AGRICULTURE. 681 



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 of the fact in 

 ,this connection. 



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 ofiSce of the Secretary of Agriculture, in such connection 

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

 fortunate practice has grown up among manufacturers of so wording 

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

 amount of a valuable constituent ranging from a certain minimum 

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

 guaranty not infrequently given. In reality, the sole guaranty is for 

 2 per cent. The guaranteed amounts given for each brand in the 

 following tables, are copied from the guaranties filed by the maker 

 of the goods with the Secretary of Agriculture, the lowest figure 

 given for any constituent being considered to be the amount guar- 

 anteed. For compactness and because no essentially important fact 

 is suppressed thereby, the guaranties for soluble and reverted phos- 

 phoric acid have not been given separately, but are combined into a 

 single guaranty for available phosphoric acid; in cases where the 

 maker's guaranty does not specifically mention available phosphoric 

 acid, the sum of the lowest figures given by him for soluble and re- 

 verted phosphoric acid is used. The law of 1879 allowed the maker 

 tc express his guaranty for nitrogen either in terms of that element 

 or in terms of the ammonia equivalent thereto; since ammonia is 

 composed of three parts of hydrogen and fourteen parts of nitrogen, 

 it is a very simple matter to calculate the amount of one, when the 

 amount of the other is given; the amount of nitrogen multiplied by 

 3 .214 will give the corresponding amount of ammonia, and the amount 

 of ammonia multiplied by 0.824 will give the corresponding amount 

 of nitrogen. In these tables, the expression is in terms of nitrogen. 



The laws of 1901 and 1909 abolished this alternative and required 

 that the guaranty shall be given in terms of nitrogen. Many manu- 

 facturers after complying ^dth the terms of the law, insert addi- 

 tional items in their guaranties, often with the result of misleading 

 or confusing the buyer; the latter will do well to give heed to those 

 items only that are given as the law requires and that are presented 

 in these tables : 



