25 



adopted tin- custom of making determinations at a temperature not far from that of the 

 average lal >oratory. I f t he alcohol tables can be revised in accordance with a standard 

 temperature ..f jo ( '. for specific gravity determinations, a very useful service will be 

 performed, especially in the interest of industrial and food chemists. 



Tin- method f..r glycerol should be made a subject for special study. Expe- 

 rience has shown that it is possible not only to increase the accuracy of the method but 

 to -horten the time of the operation. As the provisional method now stands, it appears 

 to !) rather tedious, and there are too many opportunities for error. A large error 

 undoubtedly occur- during the evaporations as well as during the repeated extractions. 

 AJeo, i' appear- that the residue weighed as glycerol is far from being pure. 



(3) The present methods for determining total, fixed, and volatile acids are exceed- 

 ingly faulty. The method for volatile acids, especially, fails to give results anywhere 

 near the truth. The difficult y lies not only in the collection of 200 cc distillate but 

 in tin* operation, which is cumbersome and unreliable. The use of litmus in the titra- 

 tions of total and fixed acids is open to criticism, as that indicator fails to show all of 

 the arid-. A -tudy of the proposed new methods is recommended. 



(4) A more comprehensive scheme for the examination of the natural coloring mat- 

 ter of wines is required. Attention is railed to the use of standard color charts as a 

 mean- \ obtaining comparable results in the hands of different persons. It is rec- 

 ommended that the a--ocjaiioM make a special .-t inly of the character and properties 

 of the coloring matter- e\i -i MIL: in genuine wine<. 



REPORT ON BEER. 



! I ! l> \ u \ \it i , ! mtociate Referee. 



Mr. Barnard. tvlVree mi l>r<>r. reported that no cooperative work 

 on the suhjrrt had hrrn duiu-. and made the following statement in 

 to the condition of the methods: 



Two yean ago I presented beer methods which have since been adopted as provi- 

 sional. I ha\e been working with those methods since that time and find no special 

 necessity for rhamrim: them. For that reason I have not made a special report on 

 Murli work, ho\\e\ cr, seems to be ne< e-sary if we must determine the different 

 kinds of beer, and 1 would only suw>t t. you the necessity for a careful study of 

 method- oi l.,-,-r an.iK -i- \\ n h -pi-cjal reference to the adoption of some method which 

 will enable IH to tell more accurately than is at pn-ent po-sible whether or not beer 

 is brewed from all malt, or part mall, or from malt substitutes. 



REPORT ON DISTILLED LIQUORS: COOPERATIVE TEST OF 

 METHODS FOR THE DETERMINATION OF FUSEL OIL. 



I'.y L. M. TOLMAN, Associate Referee. 



The cooperative work undertaken this year was a comparison of the present Allen- 

 Marquardt method, aa given in Bulletin 107, revised, page 98, and a proposed modi- 

 fication worked out by the associate referee and his assistants. The modification was 

 based on the determination of the amount of bichromate reduced in the oxidation of 

 the higher alcohol-. This method eliminates the distillation of the acids, which the 

 experiments made have shown are not completely distilled off. In order to test this 

 modified method (for details see paper, p. 206) a series of samples was prepared con- 

 taining varying amounts of pure amyl alcohol (boiling point 131 C.) in approximately 

 50 per cent by volume ethyl alcohol, and the samples sent to eighteen different labo- 

 ratories, asking for a comparison of the modified method with the present method as 

 given in Bulletin 107. Eleven reports were received, and the following table gives 



