■distillation; ^67 



or, supposing one distillation to have been previously termi- 

 nated, the stop-cock must be opened to allow the residuum 

 or vinasse to run out : through the valve in the top a stick 

 must be introduced with which the liquid can be stirred, and 

 every thing removed which would tend to form a crust upon 

 the inside of the vessel. The stop-cock may then be closed 

 and water thrown into the boiler ; this, after being stirred 

 and allowed to remain some time, is to be drawn off through 

 the stop-cock. 



To show the importance of this preliminary operation, 

 it is sufficient to observe, that if it be neglected, the sides 

 of the boiler will become encrusted with tartar and lees, 

 which will speedily give to the alcohol a disagreeable 

 flavor ; and v/hich will likewise occasion the burning of 

 the copper, since it cannot be immediately moistened by 

 the liquor. 



As soon as the boiler is thoroughly <ileansed, it may be 

 filled about three-fourths full of wine ; but before pouring the 

 wine in, the side stop-cock must be opened to allow a passage 

 for the air contained in the boiler, which would otherwise 

 throw out the wine, and likewise for ascertaining wlien the 

 charge is complete < as soon as there is a suitable quantity of 

 wine in the boiler, the fire is kindled. 



The progress which the vapor makes through the different 

 parts of the apparatus, is judged of by the heat which they 

 successively acquire, as it passes through them. 



The first product is alcohol possessing neither an agreea- 

 ble odor nor taste, and which is removed to undergo a sec- 

 ond distillation. The alcohol which follows this is highly 

 concentrated and of a good quality : the grade of it is de- 

 termined by the hydrometer, and this instrument is therefore 

 placed at the opening of the receiving vessel, (bassiot^) to in- 

 dicate .the strength of the alcohol during the whole time of 

 the operation. For some time the hydrometer indicates 

 nearly the same degree ; but as the heat of the apparatus and 

 baths increases, the aqueous particles are less perfectly con- 

 densed, and consequently the alcohol, being less concentra- 

 ted, is inferior in strength. 



When the alcohol begins to fall below 20°, (= sp. gr. of 

 0.935,) the small stop-cock in the top of the boiler is opened 

 from time to time, and a lighted taper is presented to the va- 

 por issuing through it ; when this vapor will not take fire, the 

 operation is terminated. 



If the fiame lowness of temperature could be preserved 



