ALCOHOL IN FERMENTED LIQUORS. 
263 
e acid of the metallic salt, provided the latter has not been State of alco* 
, j , . . I ■ 1 . • t 1 hot ill lernieat- 
Ided in excess, in which case a part remains undecomposed, Hquors, 
The acetate of lead and the subuitrate of tin produce the 
jsired effect of separating the colouring and acid matters, in 
le greater number of instances, but they are less rapid and 
Jrfect in their action, and not so generally applicable as the 
ibacctate of lead*, which is the substance that I commonly 
nployed. 
The following experiment was made with a view to ascertain 
le effect of this salt. 
Twenty measures of alcohol, specific gravity ,82500, were 
lixcd with eighty measures of distilled w'ater coloured with 
igwood, and rendered slightly acid by supertartrate of pot- 
ih. Four measures of a concentrated solution of the subacc- 
ite of lead were added to this mixture, and the whole poured 
pon a filter. A precipitate was thus collected of a deep purple 
olour, which appeared to consist of oxide of lead combined 
dih tartaric acid and the colouring-extractive matter. 
The filtered liquor was perfectly transparent and colourless, 
nd afforded, on the addition of subcarbonate of potash, 19,5 
icasures of alcoholf. 
Finding 
• The effect of Utis salt upon colouring matter, was first pointed out 
) be iny iMr. E. M. Noble of Chelsea. 
t Pure nibcarboiiate of potasli, obtained by igniting the carbonate, 
.•as employed in these experiments. I found tliat about 19,5 parts of 
■ cohol were separated in the conrse of four honrs, by the addition of 
) parts of the suhcarbonalo to a mixture of 20 parts of alcohol by 
»<asure with 80 of distilled wat«>r, and tiiat ho further separation took 
Mce. The alcohol b alw.ays slightly alksKne, probably from containing 
.small poriion of the solution of subcarbonate, or of pure soda, but as 
I is did not interfere with tlie object of the experiment, it was not parti- 
Ljlarly attended to. 
' When the buhearbonate was added to a mixture of four parts by 
1 oasurc of alcohol with 96 ef water, no separation was effected — A 
I ixture containing 8 percent- of alcohol afforded about 7 parts— oo« 
I 'iitaiiiing 16 percent- about 15,5, and where the proportion of alcohol 
I'.ceeded 16 per cent, the quantity, indicated by the action of tlic sub- 
ii.rbonate, was always within 0,5 per cent, of the real proportion con- 
