40 
POPULAR SCIENCE REVIEW. 
and in the course of several years sinks down to a few tenths of 
a per cent, or so, and the wine is then fit for bottling. It is 
only in rare cases that a natural wine can be safely bottled 
when it contains more than 1% of sugar. 
Fortified wines, the fermentation of which has been stopped 
by the addition of spirits, generally contain more sugar, 
ranging from 0 to 5%, and in a few liqueur wines rising even 
to upwards of 25%. The amount of sugar found in these wines 
depends, firstly, upon the amount left when fermentation was 
stopped ; and, secondly, upon the quantity added, as so-called 
saccharine, to the finished wine, this latter being very fre- 
quently done in this country. Sometimes also, a portion of 
evaporated must , which has not been subjected to any fermenta- 
tion, is added to the fortified wine. It is on this property of 
the spirit of preventing the fermentation of sugar that its chief 
use to the wine grower and merchant depends, as it makes even 
young wine at once a marketable article. The buyer is then 
obliged to keep the wine for many years in his cellar, to allow 
the injurious effects of the added spirit to disappear, and let the 
wine once more become a pleasant drink. 
In all pure or simply fortified wines by far the greater pro- 
portion of the sugar present is, as before explained, fruit sugar, 
the rest being grape sugar ; in such, to which inspissated must 
or a solution of cane sugar (saccharine) has been added, the 
proportion of grape sugar is greater, though still bearing the 
fruit sugar in excess. In wines in the preparation of which 
sugar of starch has been employed grape sugar is the predomi- 
nating kind. 
Compound Ethers . — We have before seen that whenever an 
alcohol (or several alcohols) and an acid (or several acids) are 
mixed, the formation of what are termed compound ethers 
commences. A compound ether may be looked upon as a salt 
of an acid, with an alcohol radical analogous to the ordinary 
mineral salts of the acid. 
as (K)IIO + C 2 H 4 0 2 = C 2 (K)I1,0 + II 2 0 
potash acetic acid acetate of potassium water 
and (C 2 H 5 )IIO + C 2 II 4 0 2 = C 2 (C 2 H 5 )H 3 0 + II 2 0 
alcohol acetic acid acetic ether water 
Or, expressed in words, hydrate of potassium (potash) and 
acetic acid yield acetate of potassium and water; and hydrate of 
ethyl (alcohol) and acetic acid yield acetate of ethyl (acetic 
ether) and water. 
The production of compound ethers commences as soon as 
the acid and alcohol come together ; it takes place rapidly at 
first, very slowly towards the end. If water be absent, and the 
water produced during the reaction is removed, the process goes 
