450 ANNUAL REPORT OF THE Off. Doc. 



MATERIALS USED IN FERTILIZERS. 



The sampling agents report no case of declaration under the re- 

 quirements of Section 4 of the fertilizer law, nor has microscopic ex- 

 amination shown any decisive evidence of the presence in any fer- 

 tilizer of more than accidental traces of any of the substances speci- 

 fied in that section. 



On the other hand, the results of the examination of the condition 

 of the nitrogen in the complete fertilizers by the alkaline perman- 

 ganate method affords much that is suggestive. 



To keep the tables down to convenient size, the percentages of ac- 

 tive insoluble nitrogen found have been omitted. They can be com- 

 puted, however, from the figures given, bv deducting from the total 

 nitrogen the suin of the soluble and the inactive insoluble nitrogen. 

 The ratio which the active insoluble bears to the" inactive insoluble 

 nitrogen being the principal indication the method as here used gives 

 respecting the character of the organic nitrogenous ingredients of 

 the fertilizer, the index letters, 'a', 'b', and 'c', have been affixed to the 

 percentages of inactive insoluble nitrogen, to indicate the ratios be- 

 tween the active and inactive insoluble in the several samples. Cases 

 in which the active constitutes three-fifths or more of the insoluble 

 are marked *a'; two-fifths to three-fifths, 'b', and less than two- 

 fifths, 'c' The New England Stations used the terms 'good,' 'doubt- 

 ful' and 'poor' for these respective classes of cases. 



Of tbe 503 samples examined this season, 83 belong to class 'a', 336 

 to 'b', and 84 to 'c'. 



It is needful to keep clearly in mind the meaning of the index 'c' 

 as thus applied. Its presence does not suffice to indicate that the 

 fertilizer contains no readily available nitrogen, but merely that part 

 or all of the insoluble nitrogen is derived from low grade sources, 

 barring cases in which cyanamid is one of the fertilizer ingredients. 

 These low-grade materials may be such as are listed in Section 4 of 

 the law, or others in common use, such as garbage tankage, peat or 

 mora meal; and they may, if of animal origin, have had their nitro- 

 genous materials changed almost entirely to an available condition 

 by 'wet mixing,' which has, however, little improving effect upon the 

 nitrogenous constituents of garbage tankage and mora meal, and little 

 more upon those of peat. 



The use of such low-grade materials is either to make the fertilizer 

 less likely to become sticky or lumpy, or to supply nitrogen from 

 materials that would otherwise be wholly thrown to waste. The use 

 of 'conditioners' for the former purpose is, in itself, desirable rather 

 than objectionable; but becomes obnoxious and unjust when the 

 nitrogen they contain in unavailable form is made the basis of a 

 charge at high rates to the buyer. The use also of low-grade and 

 therefore cheap nitrogen supplies whose nitrogen has, by chemical 

 treatment, been made useful for plant-food, is laudable provided the 

 materials are sold for what they are, instead of being sold at the 

 prices of the nitrogen in high-grade nitrogenous ingredients. 



In cases where the inactive insoluble nitrogen forms a large frac- 

 tion of the total nitrogen, is marked by the index 'c,' the guaranty 



