108 EXPERIMENT STATION RECORD. 



in basic slajj' were compared. The lowest results were obtained by the 

 ammonium citrate method and the highest by the Macfarlane method, 

 in which the free lime is removed from the slag l)y means of ammonium 

 chlorid before treatment with citric acid. The determinations ranged 

 from 1.54 to 10.90 per cent. The referee considered it desirable to 

 agree upon the percentage of the total phosphoric acid availa])le in a 

 sample of basic slag of standard composition and lineness. The advis- 

 ability of continuing work on basic slag was discussed, but no action 

 was taken. 



NITROGEN. 



The report of the referee on the determination of nitrogen was 

 submitted ))}' F. W. Morse. Comparisons were made of the neutral 

 permanganate method as modified lyy Street and the alkaline perman- 

 ganate method as modified by Jones for the determination of available 

 organic nitrogen in fertilizers. The materials selected for distril)ution 

 to analysts were dried blood and cotton-seed meal combined with 

 superphosphate. Results from 12 anah'sts were received. In the 

 determination of total nitrogen the weight of evidence favored a longer 

 period of digestion than usual. Duplicate determinations of availabil- 

 ity b}- any one analyst agreed well, taking each method by itself. The 

 two methods in comparison, however, gave widely varying results, and 

 neither was thought to give the available nitrogen. The referee 

 recommended further study of the two methods, which was adopted. 

 The recommendation was also adopted that in reporting analyses of 

 complete fertilizers the amounts of nitrogen existing in the form of 

 nitrates, organic nitrogen, and ammonium salts be so stated. 



In the discussion of nitrogen determination G. W. Cavanaugh 

 reported favorably upon the use of both mercuric oxid and potassium 

 sulphate and upon reversing the order of adding potassium sulphid 

 and sodium hj^droxid as given in the oflicial method. The advantage 

 gained in the latter procedure is in adding the potassium sulphid to an 

 alkaline solution and theieb}^ avoiding an evolution of hydrogen sul- 

 phid. Distillation with steam was found very efiicient in preventing 

 bumping. 



The report on the separation of nitrogenous bodies was read by the 

 referee, L. L. Van Slyke. Work along this line was confined to the 

 proteolytic products of cheese and milk and consisted in devising and 

 testing methods of separation and estimation. Credit is given to 

 E. B. Hart, of the New^ York State Station, for a large part of the 

 work. Methods for the separation and estimation of the nitrogen 

 compounds of cheese were described and discussed under the following- 

 headings: Obtaining sample; determination of total nitrogen; extrac- 

 tion of water-soluble products; determination of total water-solu])le 

 nitrogen; determination of nitrogen in the form of paranuclein, proteids 



