442 EXPERIMENT STATION RECORD. 



cial iiii'tlioils: .Mctliod I fur tdtal arscnious dxiU in Paris j^reen; tlR' electrolytic 



iiiethoil for ilcteniiiiiiiii^ ciippfr in I'aris ^rcn-n and copper carbonate; the volumetric 



. N . . 



eiher nitrate metliod for deterinininir cn ano;j;cn in potassium cyanid, .^.. silvt'r nitrate 



bein<; mibstituted for the ,„ solution; and the Kessling method for determining 



nicotin. It was also recommended that further study l)e made of the 4 nKjditications 

 of the Avery-Beans method referred to in the report for determining total arsenic in 

 Paris green, with a view to the adoption of the best modi^cation as an optional offi- 

 cial method; the volumetric method for determining copper in Paris green and 

 copper carbonate; the removal of some of the organic matter in the analysis of 

 London purple; the methods for the examination of soda lye; and especially the 

 methods for determining formaldehyde. 



ASH. 



The vacancy caused during the year by the resignation of E. G. 

 Runyan as referee on ash was filled by the appointment of G. S. Fraps, 

 Avhose report dealt with the determination of sulphur and sulphates. 

 The report called forth some discussion on the suitabilit}' of the sodium 

 peroxid method for determining total sulphur. It was stated by G. E. 

 Patrick that the use of sodium peroxid free from sitlphur was found 

 b}' him to give good results. The method for the determination of 

 sulphates, which was descril)ed in the report of the referee last year, 

 and which provides for the extraction of the substance with 1 per 

 cent hydrochloric acid, was adopted provisionally. The Association 

 approved the referee's recommendation for further study of the 

 sodium peroxid method. 



Report of referee, (J. S. Fraps.— The nitric acid method, which is the provisional 

 method of the Association, and the sodium peroxid method for the determination of 

 total sulphur were compared by 5 analysts on samples of cowpeas and cotton-seed 

 meal sent out by the referee. The average results showed that 0.466 per cent of sul- 

 phur as SO3 was obtained by the nitric acid method and 0.544 per cent by the peroxid 

 method in the case of cowpeas, and 1.048 and 1.135 per cent, respectively, in the case 

 of cotton-seed meal, showing that the nitric acid method gave lower results than the 

 peroxid method. 



Considerable difhculty was experienced by some of the analysts in the use of 

 the peroxid method. Sulphates were determined in a sample of sorghum by 4 

 analysts, the method used being that descril)ed in the report of the referee on ash 

 last year. The results obtained by the different analysts ranged from 0.324 to 0.4 

 per cent and Avere considered fairly satisfactory. The referee recommended that the 

 method referred to for the determination of sulphates be adopted provisionally, and 

 that the peroxid method of determiningsuli)hur be subjected to further study with a 

 view of replacing the nitric acid method by it. 



MISCELIANEOUS. 



W. Frear as chairman of the committee on food standards reported 

 upon the work of this committee during the j^ear. Definitions and 

 standards were formulated by the committee and submitted to the 

 Secretar}^ of Agriculture for his approval and use in fixing standards 



