520 



ANNUAL REPORT OF THE 



OS. Doc. 



Fall, 1914 

 Phosphoric acid: 



Total 



Available 



Potash 



Nitrogen, 



Spring, 1915 

 PhoKphoric acid: 



Total, 



Available 



Potash 



Nitrogen, 



9.84 

 8.41 

 3.42 

 1.29 



H>.56 

 9.05 

 3.05 

 1.95 



9.25 

 8.00 

 2.99 

 1.27 



9.34 

 S.OO 

 3.12 

 1.82 



MATEEIALS 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 

 amiuation 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. 



Ov. tlie other hand the re.«!ults 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, by deducting from the total 

 iiitJogen the sum of the soluble and the inactive insoluble nitrogen. 

 The ratio which the active insoluble bears to the inactive in.soluble 

 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' (or equivalent charac- 

 ters) have been affixed to the percentages of inactive insoluble nitro- 

 gen, to indicate the ratios between 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-fifth to three- 

 fifths, 'b', and less than two-fifths 'c'. The New England Stations 

 use the terms 'good,' 'doubtful' and 'poor' for these respective classes 

 of cases. 



Of the 233 samples examined this season, G2 belong to class 'a', 

 192 to 'b', and 22 to 'c'. 



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

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



