RECENT WORK IN AGRICULTURAL SCIENCE. 



CHEMISTRY. 



Sixth Annual Meeting of the Association of German Agricul- 

 tural Experiment Stations [Landic. Vers. tStat., 43 {1894), JS'o. 5, pp. 

 321-374). — The sixth annual meeting of this association was held at 

 Wiirzbiirg, September 8 and 9, 1893, and was presided over by F. Nobbe.^ 

 The following is a brief summary of the proceedings as affecting- 

 methods of analysis: 



Examination of Thomas slag. — The use of concentrated sulphuric acid 

 as a solvent for Thomas slag, as proposed by G. Loges, was adopted as 

 the ofldcial method without debate. The recommendations of the pre- 

 vious meeting regarding the valuation of line meal and phosphoric acid 

 in Thomas slag were also adopted after brief discussion. 



Determination of phosphoric acid. — Comparative tests by 34 stations 

 of the molybdic methods of Fresenius, Wagner, and Maercker, and of 

 the citrate method on a solution of sodium phosj)hate are reported by 

 H. Schultze and the results discussed by several others. The recom- 

 mendation of the reporter that these methods, and especially In eubauer's 

 method, be referred to the section on fertilizers for further study was 

 adopted. A motion that similar comparative tests of the methods of 

 nitrogen and potash determination be carried out was also adopted. 



Determination of nitrogen in nitrate of soda. — After general discus- 

 sion of methods, the following recommendation of Miiller was adoi)ted : 

 The nitrogen in nitrate of soda is to be determined by a direct method; 

 in addition to Kiihn's method, the methods of TJlsch, Jodlbauer, Forster, 

 and Schlosing-Grandeau may be used. Baumert specially commended 

 the Ulsch method, while Stutzer and Wagner maintained that the 

 aluminum method is unreliable. Stutzer called attention to the 

 variations in the methods of examination of nitrate of soda employed 

 by the German Agricultural Council, the German Agricultural Society, 

 the Association of Exi)eriment Stations, the German Fertilizer Manu- 

 facturers' Union, and the Union of Wholesale Fertilizer Dealers. He 

 claimed that the old difference method is still extensively used, and 

 that during the x)ast year the nitrogen content of nitrate of soda, as indi- 

 cated by this method, often fell below 15.5 per cent on account of the 

 fact that the nitrate contained a considerable percentage of potash. 

 In order that no injustice might be done, he recommended that where a 

 guaranty of 15.5 per cent of nitrogen is given a variation of 0.25 i)er 

 cent of nitrogen be allowed until July 1, 1894. 



' For proceediugs of the filth annual meeting, see E. S. R., i, p. 979. 



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