32 S EXPERIMENT STATION RECORD. 



the provisional methods for determination of acids in yard liquors. A 

 provisional met hod for the analysis of harks, woods, leaves, etc., was 

 given in detail. The referee suggested that further research he made 

 to determine the limit of temperature at which the determination of 

 soluble and insoluble matter should he carried out. 



Two papers were presented by F. P. Veitch, one on the Extraction 

 of Tannin Materials with Different Extractors, and the other A 

 Discussion of Methods for the Estimation of Tannin. 



Recainim ndations. — The recommendation of the referee that further 

 study be made to determine the limit of temperature at which soluble 

 and insoluble matter should be determined was adopted, and the method 

 described by him in his report for the analysis of barks, woods, etc., 

 was ordered printed as a provisional method, work upon it to be con- 

 tinued until it has been further perfected. The method for the deter- 

 mination of acid in tannin solutions, with the alternative of using the 

 coal-charcoal method, was continued as a provisional method, to be 

 given further stud}^; and the referee for 1905 was instructed to make a 

 study of present methods of analysis of tannery yard liquors, especially 

 spent or sap liquors. The recommendations submitted in the report 

 for 1903 (Bureau of Chemistry Bulletin No. 73) were adopted and 

 ordered to be embodied in the official methods. These changes relate 

 to weighing in a weighing bottle fitted with a glass stopper, and covering 

 the funnel with a plate during filtration to guard against evaporation. 



INSECTICIDES, FUNGICIDES, AND DISINFECTANTS. 



The report on this subject, by Bernard H. Smith, referee, was read 

 by the secretary. In general the work followed closely the lines of 

 previous years, the principal new feature being a study of disinfect- 

 ants. Results of cooperative studies were given for Paris green, 

 London purple, copper carbonate, soda lye, formaldehyde and nicotin, 

 together with the comments of the analysts. A paper on The Deter- 

 mination of Lime and Sulphur in Solutions of Sulphids or Polysulphids 

 used as Insecticides, by S. Avery, associate referee, was read by title. 



There was considerable discussion of the subject of insecticides and 

 disinfectants, attention being called especially to the poor quality of 

 commercial formalin and copper sulphate, and to the use of sulphurous 

 acid for bleaching dried fruits and grain (oats). The adoption of 

 standards for these materials was advocated by several speakers. 



Recommendations. — The modifications of the Avery-Beans method 

 for determining total arsenious acid in Paris green, noted under b, 

 p. 197, and c, p. 198, in the proceedings of the last convention," were 

 made optional methods. For the titration of arsenic twentieth-normal 

 instead of deci-normal iodin was adopted. The electrolytic method for 

 determining copper in Paris green and copper carbonate was made 



«U. S. Dept. Agr., Bureau of Chemistry Bui. 81. 



