DISTILLED LIQUORS. 



97 



(b) DETERMINATION. 



Dilute from 10 to 20 cc of the distillate as prepared under ethereal salts to 

 60 cc with furfural-free alcohol (50 per cent by volume). To this add 2 cc of 

 colorless a nil in and 0.5 cc of hydrochloric acid (sp. gr. 1.125) and keep for fifteen 

 minutes in a water bath at about 15 C. Prepare standards 

 of known strength in the same way. 



10. Fusel Oil. 

 (a) ROESE METHOD. PROVISIONAL. 



(1) PREPARATION OF REAGENTS. 



(a) Fusel-free alcohol. Prepare by the fractional dis- 

 tillation of alcohol over caustic alkali, rejecting the first 

 one -fifth and the last three-fifths of the distillate. Dilute 

 to exactly 30 per cent by volume. 



(&) Chloroform. Dry and distil. 



(c) Sulphuric acid. Specific gravity 1.2857 at 15 C. 



(2) DETERMINATION. 



Add a little alkali to 200 cc of the sample under consid- 

 er.1 1 ion (sufficient to neutralize all the acid and to saponify 

 all the esters, 20 cc normal alkali are usually enough), and 

 distil slowly, until about 175 cc have passed over, allow 

 the distilling flask to cool, add 25 cc of water and distil 

 again until the total distillate measures 200 cc. Dilute the 

 distillate to exactly 30 per cent by volume (sp. gr. 0.96541 

 at 15.6 C.). 



Prepare a water bath, the contents of which are kept at 

 exai-tly 15 C. ; place in it the apparatus (covering the end 

 of the tube with a rubber cap to prevent wetting the inside 

 of the tube) and the flasks which contain the 30 per cent 

 fux'1-free alcohol, the chloroform, the sulphuric acid, and the 

 distillate diluted to 30 per cent by volume. When the solu- 

 tions have all attained the temperature of 15 C. 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 sul- 

 phuric acid, invert the apparatus and shake vigorously for Fl<; 

 two or three minutes, interrupting once or twice to open 

 the stopcock for the purpose of equalizing pressure. Allow the apparatus to 



3. Brom well's 

 fusel oil apparatus. 



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 con- 

 traction 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 vol- 

 me 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. 



Owing to the extreme difficulty of preparing distillates of exactly 30 per cent, slight 

 variations may be corrected by increasing or decreasing the chloroform reading, as sug- 

 gested by Sell, 0.003 cc for each 0.01 per cent variation in strength of alcohol from 30 

 per cent. Such variation, however, should not exceed 0.02 per cent 



