444 
THE OPERATIVE CHEMIS" 
all which throw down a sediment. None of these should 
produce any change on genuine vinegar. 
The excise duty upon vinegar is not calculated by its own 
specific gravity, but by that of the solution of lime, formed 
by means of it, as marked by hydrometers, called acetome 
ters. The quantity of carbonate of soda it would require to 
saturate it, seems a more eligible process, and would tend 
to discourage the addition of sulphuric acid. 
Sugar Vinegar. 
Good vinegar may be made from a weak syrup, consisting 
of ten avoirdupois pounds of sugar to every eight gallons of 
water. The yeast and rape are to be here used as before 
described. 
This sugar vinegar is usually flavoured with various fruits, 
one of those most commonly used is gooseberries ; twelve 
pints of bruised gooseberries are generally mixed with the 
above proportion of sugar and water, put into stone bot 
tles of a moderate size, stopped with a loose cork, merely 
to keep out the dust, and exposed to the sun, until the 
vinegar is completed, which generally takes a whole sum 
mer. 
Whenever the vinegar is considered to be completely 
made, it ought to be decanted into tight barrels or bottles, 
and well secured from access of air. Boiling for a few 
minutes before it is bottled is found favourable to its pre 
servation. 
Distilled Vinegar. 
Vinegar, obtained by the preceding methods, has more or 
less of a brown colour, and a peculiar, but rather grateful, 
smell. By distillation in glass vessels, the colouring matter, 
which resides in a mucilage, is separated; but the fragrant 
odour is generally re-placed by a burnt or smoky smell and 
taste. 
The best French wine vinegars, and also some from malt, 
contain a little alcohol, which comes over early with the 
watery part, and renders the first product of distillation 
scarcely heavier, sometimes even less heavy, than water. It 
should accordingly be rejected. 
Towards the end of the distillation, the burnt odour and 
taste increases. Hence, only the intermediate portions are 
retained as distilled vinegar. The specific gravity varies 
from 1•005 to 1•015, while that of common vinegar of equal 
strength, varies from 1•010 to 1:025.