98 EXPERIMENT STATION EECORD. 



The associate referee on phosphoric acid, A. J. Patten, discussed the use of 

 the electrical conductivity method for determining the neutral point in prepar- 

 ing ammonium citrate solution. The method in his hands gave better results 

 than the usual procedure. 



The referee on nitrogen, J. W. Kellogg, made no definite report, but recom- 

 mended that the method for determining available nitrogen be continued, and 

 that the alkaline and neutral i>ermanganate methods as applied to crude stock 

 be further studied. E. L. Baker recommended on the basis of his results that a 

 trial be made of the Salle method (E. S. R., 23, p. 213) for nitrates and nitrites 

 in commercial nitrates. 



As referee on potash, Mr. Baker reported cooperative work which was prac- 

 tically a repetition of that of last year with a few minor changes and which 

 gave in general good results. He recommended that the study of the Drushel 

 volumetric cobalti-nitrite method be discontinued and the gravimetric cobalti- 

 nitrite method be studied, using in this connection the Itano method of precipi- 

 tating out the phosphates before adding the reagents. 



A paper submitted by M. A. Drushel on the estimation of potassium as 

 cobalti-nitrite was read by L. L. Van Slyke, in which a plea was made for the 

 retention of this method but applying it only to fertilizers containing less than 

 10 per cent of potash. L. T. Bowser also rendered a report on the cobalti- 

 nitrite method. A resolution was iutroduced in connection with potash to make 

 the factors for calculating from potassium platinic chlorid to potassium chlorid 

 read 0..S067. to potassium sulphate to i*ead 0.3585, and to potassium oxid to read 

 0.1938, and, furthermore, to make certain modifications in the official method. 



J. G. Lipman and G. S. Fraps, referee and associate referee, respectively, on 

 soils, reported giving some time to bacteriologic methods for determining soil 

 acidity and also to the modified cobalti-nitrite method for potash and methods 

 for humus determination. In the case of the latter it was pointed out that 

 the official method for humus is less accurate than the Mooers-Hampton and 

 the llather methods (E. S. R., 25, p. 614). The referees recommended a fur- 

 ther study of the Rather method and the elimination of the official method. 



As the referee on inorganic plant constituents, O. M. Shedd reported ou co- 

 operative work done in regard to the molybdate method for separating ferric 

 and aluminic oxids. Recommendations were made to adopt officially the 

 molybdate method, to study further the oxalate method with a synthetic ash 

 solution, and to study the Schreiber method (E. S. R., 23, p. 215) for total 

 sulphur in organic matter. The referee on water, W. W. Skinner, in addition 

 to giving the results of the cooperative work, advocated the adoption as official 

 of methods proposed in Circular 52 of the Bureau of Chemistry (E. S. R., 22, 

 p. 614). 



C. C. McDonnell, the referee on insecticides, made several recommendations 

 in regard to the chromate method for total lead oxid and lead arsenate, the 

 gravimetric method for sulphur as sulphids and polysulphids in lime-sulphur 

 wash, the volumetric method for sulphur present as thiosulphate in lime-sul- 

 phur solution, the arsenious and arsenic acid in London purple, and the Gate- 

 house method for determining chlorin in cyanids. 



The referee on food adulteration, A. S. Mitchell, gave an outline of some of 

 the work conducted during the past year by the associate referees and others. 

 The associate referee on the adulteration of dairy products, A. E. Paul, pointed 

 out the possibilities for fraud by the use of the homogenizer in the dairy and 

 ice-cream industries, and also introduced a method for extracting fat from 

 cream, ice-cream, evaporated milk, and sweetened condensed milk. 



