CONVENTION OF OFFICIAL AGRICULTURAL CHEMISTS. t25 



solution in computing the percentage of reducing sugars were appro> ed 

 by the association. 



P. II. Walker read a paper entitled A Uniform Method for the 

 Determination of Reducing Sugars, in which a modified method for 

 the determination of both dextrose and invert sugar was described. 

 This was designed toavoid confusion in work on reducing sugars aris 

 ing from using Allihn's tables for dextrose and MeissPs babies for 

 in\ erf sugar. 



TANNIN. 



The report of the referee, H. C. Reed, contained the results of 

 extended collaborative investigations, and was presented only in 

 abstract. The following subjects were recommended for collaborative 

 research during the coming year: (1) Soluble solids filtration, (2) 

 analysis of liquors and the effect of the acidity of the liquors upon the 

 analysis. (3) estimation of acid in tan liquors, (I) the influence of 

 acidity and alkalinity upon the chroming of hide powders and upon the 

 subsequent analysis, (5) extraction, (6) the Parker-Payne method of 

 tannin analysis, and (7) estimation of nitrogen in leather and tan 

 Liquors. Methods adopted provisionally included the chroming of 

 hide powder by the addition of the entire amount of chrome alum at 

 one time, limiting the moisture content of wet chromed hide powder 

 used for analysis between To and 75 per cent, the analysis of liquors 

 as detailed in the report of the referee, and use of the form of appa- 

 ratus known as the combined evaporator and drier. Action was de- 

 ferred until the next meeting upon a method for tannin analysis w hich 

 was proposed for an official method. 



A paper on the Extraction of Tanning Material for Analysis was 

 presented by F. P. Veitch. 



A communication was received from a committee representing the 

 American Leather Chemists' Association iii which it was suggested in 

 substance that the two associations appoint the same referees, or l lint 

 the Association of Official Agricultural Chemists abandon work on 

 tannin. The communication was referred to the referee for report :it 

 the next meeting. 



[NSECTICIDES, PI NGICIDES, AND DISINFECTANTS. 



The report on this subject was submitted by the referee. B. II. Smith. 

 The work followed suggestions of the previous referee, and included 

 comparative analyses by several chemists of sample- of Paris green, 

 London purple, tobacco extract, soda lye. sulphur dip, formaldehyde, 

 chlorid of lime, and a phenolic disinfectant. An examination of 28 

 samples of commercial formaldehyde from various sources showed an 

 average strength of approximately 37 per cent of formaldehyde. The 



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