If the quantities of oil are increased, they will exceed the power both of the acids naturally contained in the must, and of those absorbed from the air in fermenting; the liquor will therefore require a longer time before it becomes pellucid, unless assisted by precipitation: and there may be cases where even precipitation cannot fine it. These considerations naturally lead us to a general division of wines into three classes: First, of such as soon grow fine, and soon become acid, being the growth of cold countries. Secondly, of those which, by a due proportion of heat, both when the grapes germinate, and when they come to maturity, form a perfect must; and not only preserve themselves, but, in due time, (more especially when assisted by precipitation,) become transparent; and, thirdly, of such as, having taken their first form under the highest degrees of _germination_, (as I termed them) are replete with oils, disappoint the cooper, and render the application of menstruums useless, unless in such quantities as to change the very nature of the wine. This remarkable difference in wines appears chiefly to arise from the climate; and it will confirm the observation before made, that, as wines are neither naturally nor uniformly perfect, they must be subject to many diseases. All vegetable substances possess fermentable principles, though in a diversity of proportions; for those juices only, whose constituent parts approach to the proportion necessary for the act of fermentation, can be made into wines. I would not, however, from what I have attributed to a difference of heat in different climates, be understood, as if I thought that vegetables are more or less acid, more or less sulphureous, or in general more or less fermentable, merely from the heat of the country they grow in. This, though likely one of the principal causes of their being so, is by no means the only one; the form and constitution of the plant is another. In very hot climates, we find acid fruits, such as limes, tamarinds, lemons, and oranges; the proportions of fermentable principles in these fruits are such, as to render them incapable of making sound wines, though their juices may, in some degree, be susceptible of fermentation. In countries greatly favored by the sun, some vines and other fruit trees there are, which attract the acids from the air, and possibly from the earth, so greedily, that, when their juices are fermented, they soon become sour. On the contrary, in cold climates, we see warm aromatic vegetables grow, as hops, horse-raddish, camomile, wormwood, &c. whose principles cannot, without difficulty, and perhaps not perceptibly, be brought to ferment. But these instances must be accounted the extremes on each sides; for in cold, as well as in hot countries, fruits are produced susceptible of a perfect natural fermentation: with us, for example, apples; some species of which are endued with such austere and