If I had not already said enough to convince the brewer of the utility of this instrument, how curious he ought to be in the choice, and how well acquainted with the use of it, I should add the heat gained by the effervescing of malt, is to be determined by it alone; the quantity of heat lost by mashing, by the water in its passage from the copper to the mash ton, and by the extract coming down into the underback, these can be found by no other method; and, above all, that there is no other means to know with certainty the heat of every extract. I know very well good beers were sometimes, perhaps often, made before the thermometer was known, and still is, by many who are entirely ignorant of it; but this, if not wholly the effect of chance, cannot be said to be very distant from it. They who carry on this process, unassisted by principles and the use of the thermometer, must admit they are frequently unsuccessful, whereas did they carefully and with knowledge apply this instrument, they certainly would not be disappointed.—It is equally true, the brewing art, for a long space of time, has been governed by an ill-conveyed tradition alone; if lucky combinations have sometimes flattered the best practitioners, faulty drinks have as often made them feel the want of certain and well established rules. It is just as absurd for a brewer to refuse the use of the thermometer, as it would be for an architect to reject the informations of his plummet and rule, and to assert they were unserviceable because the first house, and probably many others, were built without their assistance. SECTION VII. OF THE VINE, ITS FRUITS, AND JUICES. After these short accounts of the principles and instrument necessary to the right understanding of the brewing art, we should now draw near to the particular object of this treatise, but as the most successful method to investigate it, must be first to inspect the great and similar example nature has set before us, our time will not be lost by making this enquiry. Any fermented liquor, that, in distillation, yields an inflammable spirit miscible with water, may be called wine, whatever vegetable matter it is produced from.—As beer and ales contain a spirit exactly answerable to this definition, brewing may justly be called the art of making wines from corn. Those, indeed, which are the produce of the grape, have a particular claim to the name, either because they are the most ancient and the most universal, or that a great part of their previous preparation is owing to the care of nature itself. By observing the agents she employs, and the circumstances under which she acts, we shall find ourselves enabled to follow her steps, and to imitate her operations.