WINES. 



according to the quantity, and shaken up with 5cc. beuzoyl chloride 

 and 35cc. of 10 per cent, soda solution for 10-15 minutes without ces- 

 sation and with frequent cooling. The estergemenge or precipitate ob- 

 tained, is collected upon a filter, washed and dried for 2 to 3 hours at 

 100 0.; 0.385 gram of the weighed precipitate corresponds to 0.1 gram 

 glycerine." The objection to this process seems to be that it is not ap- 

 plicable directly to the wine or beer, but the glycerine must be separated 

 out in a state of comparative purity before it can be converted into the 

 benzoate, and there is still the liability to loss during the process of 

 purification. 

 The results given in the table are by the old method. 



TANNIN. 



The estimation of tannin in wines, where considerable accuracy is re- 

 quired, may be made by the permanganate and indigo method, which 

 has been so much discussed and modified in chemical literature. The 

 following approximate method is given by the Berlin Commission: 



In lOcc. of wine the free acids are, if necessary, reduced by the addition of 

 standard alkali solution to .5 grams in lOOcc. Then Ice. of a 40 per cent, solution of 

 acetate of soda is added, and finally, drop by drop, 10 per cent, solution of chloride of 

 iron, avoiding an excess. One drop of the chloride of iron solution suffices for the 

 precipitation of about .05 percent, of tannin. 



For the estimation of the bulk of the precipitate test-tubes are used, 

 which are much narrowed at the bottom, with the constricted portion 

 graduated into tenths of a centimeter. The following table gives 

 the approximate content of tannin from the bulk of the precipitate after 

 standing twenty-four hours : 



I can see no practical conclusions to be drawn from so indefinite a 

 determination and have omitted ib in my work, simply quoting it for 

 the benefit of any one who might desire to make the estimation. 



