36 FALSIFICATION OF WINE VINEGAR, &C. ' 
eighth of its volume, allow it to cool, the residuum is treated 
with four times its weight of alcohol at 40°; the alcoholic so- 
lution is filtered; distilled water is added; the alcohol is eva- 
porated; then the solution of muriate of baryta is added until 
no more precipitate is thrown down; the precipitate is col- 
lected on a filter, washed with boiling water, dried, weighed 
and the weight of the acid deducted. 
A very simple method of detecting the presence of sulphu- 
ric acid in vinegar is the following.* Take a certain quantity 
of the vinegar supposed to be adulterated, place it in a small 
porcelain capsule, or a platina vessel is better, then heat it to 
entire evaporation. If the vinegar does not contain sulphuric 
acid, the vapour which arises during evaporation, does not 
possess any peculiarity; if, on the contrary, it contains this 
acid, at the end of the operation, the vapour of sulphuric acid 
becomes apparent, which is white, dense and suffocating. This 
extremely simple manner of recognising the falsification of 
vinegar by sulphuric acid, does not indicate the proportion of 
the sulphuric acid introduced. 
Methods of recognising the falsification of vinegar by 
muriatic acid. 
Many modes have been proposed to detect this adulteration; 
the best is the following; take 100 grammes of vinegar, place 
it in a retort and submit it to distillation continued a sufiicient 
length of time and so as to drive over all the acid into the re- 
ceiver, then pour upon the distilled product a solution of ni- 
trate of silver, which if the vinegar is pure should afford no 
precipitate, and which furnishes a white curd-like precipitate, 
insoluble in nitric acid, soluble in ammonia, if the vinegar 
contains muriatic acid. The precipitate of chloride of silver, 
is collected on a filter, washed and dried, then from its weight 
deduct the weight of the muriatic acid upon the basis of the 
established formulae which assume that 100 parts of silver 
* This method has been tried in the presence of several persons and it 
has appeared exceedingly simple and very convenient. 
