EXPERIMENT STATION RECORD. 



Vol. 2. OCTOBER, 1890. No. 3. 



EDITORIAL NOTES. 



The seventh aunual couventiou of the Association of Official Agri- 

 cultural Chemists was held iu the lecture room of the National Mui^eum 

 at Washington, August 28, 29, and 30. The attendance was larger 

 than that of any previous meeting. About forty chemists were present. 

 Twenty experiment stations were represented. The meeting was marked 

 by earnestness of purpose, strict attention to the work in hand, mani- 

 fest disposition on the part of the members to study more closely and 

 thoroughly the questions involved before taking decisive steps, and an 

 increased tendency towards conservatism in regard to alterations la 

 methods. 



The results returned by those who had co-operated in the analyses of 

 materials sent out by the reporters on different subjects, while they 

 differed widely in many cases, were, on the whole, an improvement over- 

 last year's. In the nitrogen determinations especially, the agreement 

 of results by different analysts was much better. The changes adopted 

 in the methods of last year, which will be better understood by refer- 

 ence to the proceedings of the last convention,* are in substance as 

 follows : 



Nitrogen: Kjeldahl method. — The determination of the absolute 

 strength of the standard hydrochloric acid solution by means of sodium 

 carbonate was discarded ; in standardizing with either potassium tetrox- 

 alate, or ammonia distilled from ammonium chloride and sodium hy- 

 droxide, cochineal or dimethyl aniline orange is to be used as an indi- 

 cator. For the digestion, in place of 0.7 gram of mercuric oxide, its 

 equivalent of metallic mercury may be used. To prevent bumping of 

 the solution in distilling, the addition of 0.5 gram of zinc dust is recom- 

 mended, instead of granulated zinc. In the determination of nitrogen 

 in Jiitrates, zinc sulphide may be employed in place of zinc dust. If 

 zinc sulphide is substituted for zinc dust one gram of salicylic acid may 



"Bullefm No. 24 of the Division of Chenaistrj of the U. S. Department of Agricult^ 

 ure. 



89 

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