THE MAKING OF WINE--FERMENTATION. The must, as we have already seen, is the juice of the grape, which has been squeezed out by the grape-mill or from the wine-press. The murk, or pomace as it is called in America, on the contrary, is the mass of grape skins, stalks, &c., left behind in the press. A clear apprehension of these two terms is required in order that no confusion may arise. The fermenting-vat is the cask in which what is called the strong, stormy, or tumultuous fermentation takes place. The "cuvage" is the length of time the contents are left in the fermenting-vat. The whole phenomena of fermentation are too complicated and profoundly scientific to be dealt with here. I shall do no more, therefore, than briefly refer to the behaviour of the must in the fermenting-vat. Fermentation sets in soon after the must is placed within the latter. The germs of vinous fermentation are contained in abundance in the air of the wine cellar, as well as being on the grapes themselves. M. Pasteur, who has contributed so much to a proper understanding of fermentation, has proved that the yeast fungi come from the external surface of the grapes, and are not derived from the interior. Hence it follows that the skins are to be well crushed before fermentation begins, to ensure proper action in the must. The temperature of the must soon begins to rise, and the fermentative agencies break up its glucose into alcohol and carbonic acid gas. There is a bubbling and seething in the liquid during this action, which gradually subsides. The increase of temperature in the fermented fluid begins to abate; the skins and husks subside to the bottom of the vat; the liquid itself becomes slightly less turbid--and the first stage of wine-making is at an end. A clearer insight into this important part of the process will perhaps be gained by noting some of the practices followed on the Continent, as regards the duration of the vattage. The length of time the various contents--whether they be the grape juice alone, or the grape juice together with the skins and stalks--remain within the fermenting-vat, varies greatly in different parts. In the Champagne country, the must is allowed to stand for twelve or eighteen hours, during which time a froth arises to the top and a sediment descends to the bottom. Without disturbing either of these, the precious liquid is carefully withdrawn into small barrels, and the fermentation is then allowed to proceed. This purification is one of the most important matters connected with the making of champagne.