156 
POPULAR SCIENCE REVIEW. 
dominate, though to a less extent than in sherry. Indeed, the 
art of cultivation of the vine and the treatment of the must , 
&c., is nearly the same as in Spain. East and West India 
Madeira is such as has been shipped once or twice to one or other 
of the above places respectively, or has even been stored there 
for some time. The high temperature to which the wine is 
thereby exposed considerably facilitates the maturing of the 
wine, which thus improves more rapidly, and perhaps to a 
higher degree, than it otherwise would do. Madeira is a full- 
bodied wine, of excellent keeping quality, and when mellowed 
by age or high temperature, of extremely fine flavour and 
aroma. 
Port Wine is the produce of a district called the Alto Douro, 
or Upper Douro, about 50 miles east of Oporto in Portugal. 
The vineyards are situated on both banks of the river, and the 
wine produced is sent by boats to Oporto, where it is classified, 
stored, &c. From the circumstance of its being exported thence 
is derived its generic name of port. The district of the Alto 
Douro is capable of producing, in favourable seasons, upwards 
of 8,000,000 gallons of wine. Port wine is also a brandied 
wine, its alcoholic strength ranging generally from 15 to 20%. 
The total amount of acid it contains is somewhat less than in 
Ithine wines, but the volatile acid is somewhat greater in amount, 
and it contains scarcely any tartaric acid, cream of tartar being 
almost insoluble in the strong wine. In spite, however, of this 
higher proportion of volatile acid, the volatile ethers are found 
in less proportion than the fixed ethers ; the wine, when young, 
has in consequence less bouquet than the preceding. As fer- 
mentation has been prematurely suppressed the wine contains a 
variable amount of sugar, depending of course upon the period 
at which fermentation was interrupted, or on the amount of 
inspissated must added subsequently; it averages from 2 to 
6%. It contains also much tannin and colouring matter 
from the stones and husks of the grape (or elderberry ?), 
and comparatively a large proportion of albuminoid substance 
which, owing to incomplete fermentation, has not been precipi- 
tated. It leaves in general but a moderate amount of ash, 
though rather more than either hock or claret, and of very 
much the same composition as in these two wines. 
As the wine gets older, some tartar, much colouring matter, 
tannin, and albuminoid substance are thrown down, and it loses 
some of its sugar and increases in acidity (acetic acid). Mean- 
while, the volatile ethers appear gradually to gain on the fixed 
ethers, so that in old wines they equal or even exceed them in 
amount ; the wine approaches in this respect more and more 
to the natural standard. 
Port wine, when new, has but little bouquet, is rather rough 
