Mr GRAHAM'S Account of the Formation of Akoates. 179 



is to be apprehended from a complete than from an imperfect 

 exhaustion. After producing the exhaustion, no farther atten- 

 tion would be necessary ; and upon opening the box at the ex- 

 piration of a week or ten days, the alcohol would be found an- 

 hydrous. It is evident that absolute alcohol, procured by this 

 process, could be sold at a price but little exceeding its original 

 cost. It would moreover be of much greater value for the pur- 

 poses for which it is employed in the arts and medicine. I be- 

 lieve, however, that, by the excise laws as they at present exist, 

 no rectifier of spirits is permitted to concentrate alcohol beyond 

 a certain strength. Licensed apothecaries alone are allowed to 

 prepare and sell absolute alcohol. * 



Alcohol may be concentrated in a close vessel with quicklime, 

 without exhausting ; but the process goes on much more slowly, 

 at least at the temperature of the air. The experiment was 

 tried at a high temperature, by heating in a water-bath a large 

 bottle with a very wide mouth, containing a quantity of alcohol 

 at the bottom, and quicklime suspended over it in a linen-bag. 

 When the water-bath attained the temperature of 150, the 

 bottle was corked, and the bath prevented from becoming hotter. 

 Much of the lime was very quickly converted into hydrate, and 

 the alcohol considerably concentrated. But the process is trou- 

 blesome, and much inferior to that in which the air-pump is 

 employed. 



In the place of quicklime, sulphuric acid cannot be substituted 

 in the foregoing process as an absorbing liquid, from a remark- 



* Care should be taken that the temperature be nearly equable during the expe- 

 riment ; otherwise, when the atmosphere becomes cold, a condensation of alcohol 

 vapour takes place upon the cooled bell-glass, which runs down upon the plate of 

 the pump. The experiment, therefore, should not be performed in a room with a 

 fire, or near a window, but in a dark closet or press. From the manner in which I 

 performed the experiment, this condensation had never been experienced by myself; 

 but Dr DnNCANjMnior observed it, on repeating the process. 



z 2 



