Every body knows that no product of the arts varies so much as wine; that different countries, and sometimes the different provinces of the same country, produce different wines. These differences, no doubt, must be attributed chiefly to the climate in which the vineyard is situated--to its culture--the quantity of sugar contained in the grape juice--the manufacture of the wine; or the mode of suffering its fermentation to be accomplished. If the grapes be gathered unripe, the wine abounds with acid; but if the fruit be gathered ripe, the wine will be rich. When the proportion of sugar in the grape is sufficient, and the fermentation complete, the wine is perfect and generous. If the quantity of sugar be too large, part of it remains undecomposed, as the fermentation is languid, and the wine is sweet and luscious; if, on the contrary, it contains, even when full ripe, only a small portion of sugar, the wine is thin and weak; and if it be bottled before the fermentation be completed, part of the sugar remains undecomposed, the fermentation will go on slowly in the bottle, and, on drawing the cork, the wine sparkles in the glass; as, for example, Champagne. Such wines are not sufficiently mature. When the must is separated from the husk of the red grape before it is fermented, the wine has little or no colour: these are called _white_ wines. If, on the contrary, the husks are allowed to remain in the must while the fermentation is going on, the alcohol dissolves the colouring matter of the husks, and the wine is coloured: such are called _red_ wines. Hence white wines are often prepared from red grapes, the liquor being drawn off before it has acquired the red colour; for the skin of the grape only gives the colour. Besides in these principal circumstances, wines vary much in flavour. All wines contain one common and identical principle, from which their similar effects are produced; namely, _brandy_ or _alcohol_. It is especially by the different proportions of brandy contained in wines, that they differ most from one another. When wine is distilled, the alcohol readily separates. The spirit thus obtained is well known under the name of _brandy_. All wines contain also a free acid; hence they turn blue tincture of cabbage, red. The acid found in the greatest abundance in grape wines, is tartaric acid. Every wine contains likewise a portion of super-tartrate of potash, and extractive matter, derived from the juice of the grape. These substances deposit slowly in the vessel in which they are kept. To this is owing the improvement of wine from age. Those wines which effervesce or froth, when poured into a glass, contain also carbonic acid, to which their briskness is owing. The peculiar flavour and odour of different kinds of wines probably depend upon the presence of a _volatile oil_, so small in quantity that it cannot be separated. EASY METHOD OF ASCERTAINING THE QUANTITY OF BRANDY CONTAINED IN VARIOUS SORTS OF WINE.