8 



' ' This apparatus consists of a pear-shaped bulb holding about 200 cc, stoppered 

 at the upper end and sealed at the lower to a graduated stem about 4 mm in 

 internal diameter. To the lower end of this graduated stem is sealed a bulb of 

 20 cc capacity, the lower end of which bears a stopcock tube. The apparatus is 

 graduated to 0.02 cc, from 20 cc to 22.5 cc. 



"The reagents required are fusel-free alcohol that has been prepared by frac- 

 tional distillation over caustic soda or caustic potash, and diluted to exactly 30 

 per cent by volume (sp. gr., 0.96541), chloroform freed from water and redistilled, 

 and sulfuric acid (sp. gr., 1.2857 at 15.6). 



"Distill slowly 200 cc of the sample under examination till about 175 cc have 

 passed over, allow the distilling flask to cool, add 25 cc of water, and distill again 

 till the total distillate measures 200 cc. Dilute the distillate to exactly 30 per 

 cent by volume (sp. gr., 0.96541 at 15.6). 



"The following is an accurate method for diluting any given alcohol solution 

 to a weaker solution of definite percentage : Designate the volume percentage of 

 the stronger alcohol by V, and that of the weaker alcohol by v. Mix v volumes 

 of the stronger alcohol with water to make V volumes of the product. Allow 

 the mixture to stand till full contraction has taken place, and till it has reached 

 the temperature of the original alcohol and water, and make up any deficiency 

 in the V volumes with water. 



''Example. It is desired to dilute a distillate containing 50 per cent of alcohol 

 by volume until it contains 30 per cent. To 30 volumes of the 50 per cent alcohol 

 add enough water to make 50 volumes, or place 150 cc of the distillate in a 250 cc 

 flask, fill to the mark with water, mix, cool, and fill to the mark again. 



"Prepare a water bath, the contents of which are kept at exactly 15, and place 

 in it the apparatus (covering the end of the tube with a rubber cap to prevent 

 wetting the inside of the tube), and flasks containing the 30 per cent fusel -free 

 alcohol, chloroform, sulfuric acid, and the distillate diluted to 30 per cent by 

 volume. When the solutions have all attained the temperature of 15, fill the 

 apparatus to the 20 cc mark with the chloroform, drawing it through the lower 

 tube by means of suction, add 100 cc of the 30 per cent fusel-free alcohol and 1 cc 

 of the sulfuric acid, invert the apparatus, and shake vigorously for two or three 

 minutes, interrupting once or twice to open the stopcock for the purpose of 

 equalizing pressure. Allow the apparatus to stand ten or fifteen minutes in 

 water that is kept at the temperature of 15, turning occasionally to hasten the 

 separation of the reagents, and note the volume of the chloroform. After thor- 

 oughly cleansing and drying the apparatus, repeat this operation, using the 

 diluted distillate from the sample under examination in place of the fusel -free 

 alcohol. The increase in the chloroform volume with the sample under exami- 

 nation over that with the fusel -free alcohol is due to fusel oil, and this difference 

 (expressed in cubic centimeters), multiplied by the factor 0.663, gives the volume 

 of fusel oil in 100 cc, which is equal to the percentage of fusel oil by volume in 

 the 30 per cent distillate. This must be calculated to the percentage of fusel oil 

 by volume in the original liquor. 



"Example. A sample of liquor contains 50 per cent of alcohol by volume. 

 The increase in the chloroform volume with the 30 per cent fusel-free alcohol is 

 1.42cc; the increase in the chloroform volume with the distillate from the 

 liquor under examination, diluted to 30 per cent, is 1.62 cc: difference, 0.20 cc. 

 The volume of fusel oil in 100 cc of the 30 per cent distillate then is 0.20x0.663= 

 0.1326 cc, and by the proportion 30 :50 : : 0.1326 : 0.221, we obtain the percentage 

 of fusel oil by volume in the original liquor. 



