CONVENTION OF OFFICIAL AGRICULTURAL CHEMISTS. 183 



111 a paper entitled ''A metliod for the determiuatiou of phosphoric 

 acid ill soils," A. Goss suggested the following modification of the 

 Kjeldahl method as adapted to this purpose: Ten grams of air-dry 

 soil, 0.7 gm. of mercuric oxid, and 20 to 30 cc. of concentrated sul- 

 phuric acid are boiled in a digestion flask for 1 hour: 100 cc. of water, 

 5 cc. of hydrochloric acid, and 2 cc. of nitric acid are added, and the 

 whole boiled gently for 2 minutes. The solution is made up to 250 cc. 

 and 100 cc. taken for precipitation; 75 cc. of molybdic; solution is then 

 added, and the contents of the flask kept at 80'^ C. for 15 minutes, 

 shaking 4 or 5 times. After standing 10 minutes the solution is 

 filtered, with gentle suction. The method is then proceeded with as 

 usual, observing certain minor precautions which are enumerated. 

 Experimental data upon which the various provisions of this method 

 rest are given in detail. 



In "A note on the direct determination of potash in the soil solu- 

 tion," A. M. Peter reports the results of direct evaporation of an aliquot 

 part of the hydrochloric-acid solution with an excess of platinic chlorid, 

 which agree closely with those obtained by the provisional method. 



)Sugar. — A brief report on sugar was presented by G. L. Spencer. 

 The work of the year related to the determination of moisture (1) by 

 the official method,' (2) by drying in a vacuum for 5, 15, 20, and 10 

 hours, and (3) by the paper coil or Josse method. Three Association 

 chemists and two refinery chemists took part in this work. The results 

 indicated that the official method is fully equal, if not superior, to the 

 other methods tested, and rendered inadvisable recommendations of 

 any modification of present methods of analysis. Further investiga- 

 tion of methods of moisture determination during the coming year was 

 recommended. 



A paper "On the determination of cane sugar in the presence of com- 

 mercial glucose," by H. A. Weber and Wm. McPherson, was presented. 

 The authors reported an investigation of methods of acid reversion of 

 sucrose in the presence of dextrin and glucose, and the subsequent 

 determination of the invert sugar by means of Fehling's solution or 

 the polariscope. The results show a slight error in these methods, due 

 to hydration of dextrin, which may be reduced to a minimum by heat- 

 ing for 10 minutes, gradually bringing the temperature to 08° C. at the 

 end of that time. It was also found that acetic acid inverts glucose 

 completely, and that where Fehling's solution is used for determining- 

 sucrose in ])resence of commercial glucose it is preferable to hydro- 

 chloric acid for inversion. 



Fermented and distilled liquors. — The reporter on the subject of fer- 

 mented liquors, C. A. Crami^ton, being debarred by the Treasury offi- 

 cials from participating in this work, a report by G. E. Colby on 

 analyses by 8 chemists of a dry red wine by official methods was read 

 by H. W. Wiley. The results were generally satisfactory, and indi- 



' U. S. Dept. Agr., Div. of Chom. Cul. 38, p. 179. 



