212 Chemistry. [Lecture 31. 



tained pure by means of an elective attraction. 

 An ordinary fixed alkali, as pearl ashes, is added 

 to it, which attracts the water, is dissolved, and 

 sinks with the water to the bottom ; after this 

 pour off the spirit, and add more alkali, which 

 will not be dissolved, but moistened ; repeat the 

 operation till you observe the alkali perfectly 

 dry, when you may conclude that all the water 

 is separated. By these repeated decantations we 

 may render the spirit sufficiently strong ; but the 

 alkaline salt acting on the oily matter imparts to 

 the spirit a yellow colour, and part of the alkali 

 being dissolved with it, gives the spirit a dis- 

 agreeable taste. In order to separate this and 

 the oil which still remains, it is necessary to 

 distil the spirit in a more gentle heat ; and some, 

 thinking that the alkali may still rise, advise a 

 quantity of burnt alum to be added, that it may 

 convert the alkali into a sulphat of potass ; but 

 without this addition, if the heat is gentle, we 

 obtain the spirit free of the alkali, which, when 

 quite pure and transparent, is called ALCOHOL. 



The stronger any spirit is, the lighter it is. In 

 judging of spirits, dealers trust to proof by the 

 bell as it is called. For if brandy, containing 

 equal parts of spirit and water, is shaken vio- 

 lently, bubbles are found of a particular size, 

 which remain for a certain length of time, and 

 arrange themselves round the sides of the phial. 

 The particular size is known by experience, but 

 the appearance is different if the spirit is either 



