and other Fermented Liquors. 149 



separated by the subsequent addition of dry subcarbonate of 

 potassa, in the same manner as from whisky, gin, and brandy. 



The first of the above statements has been shewn to be true 

 by Gay Lussac (Ann. de Chim. Ixxxvi. 175). The correctness 

 of the second was demonstrated by Mr Brande, upon a sug- 

 gestion, contained in a notice, of his first paper contained in the 

 Edinburgh Review. I confirmed the results of Mr Brande's 

 experiments on this point, in the case of three kinds of wine, 

 viz. Madeira, Torres Vedras, and Claret. 



The last, however, is the most conclusive of all proofs in fa- 

 vour of this view of the constitution of wine, as by the process 

 here referred to, the alcohol may be separated from wine with- 

 out the intervention of heat. We are indebted to Mr Brande 

 for having first pointed out a mode of effecting this object (Phi- 

 losophical Transactions for 1813). This consists in adding to 

 the wine a solution of subacetate of lead, filtering the liquor, 

 and then adding to the filtered liquor dry subcarbonate of pot- 

 assa. The metallic oxide, as he says, forms a dense precipitate 

 with the acid and colouring extractive matter of the wine ; by 

 filtration a colourless fiuid is obtained, from which the alcohol 

 may be separated, as above mentioned. Mr Brande also states, 

 that the acetate of lead and subnitrate of tin, produce the de- 

 sired effect of separating the colouring and acid matters, in the 

 greater number of instances ; and to these, I may add, the pro- 

 tomuriate of tin, and the protonitrate of mercury, which I found 

 to answer in most cases. 



Observing the efi'ect of adding the subcarbonate of potassa to 

 wine, viz. that of causing effervescence, and the forming of a 

 flocculent precipitate, I was led to infer, that the compound thus 

 formed interfered with the separation of the alcohol. To de- 

 termine whetlier this opinion was correct, I added the subcar- 

 bonate to a portion of wine, as long as it produced the effect just 

 mentioned, when the whole was thrown upon a filter. The fil- 

 tered liquor was of a somewhat darker colour than the wine; 

 but when the subcarbonate was now added to it, the separation 

 of tlie alcol)ol was speedily effected. 



This result was also produced, when I employed a solution 



of ammonia, instead of the carbonate of potash ; the ffocculent 



precipitate thus formed, being separated l)y filtration, the alco. 



hoi appeared, as in the former case, upon the addition of a due 



