By applying the thermometer to the extracts, more particularly to the first, the brewer thereby will be informed, to a sufficient degree of exactness, of the defects he can mend, and hardly be ever at a loss for the properest means to work the grain to the greatest advantage. As far as we have proceeded in our enquiry, though some satisfaction must arise from our being enabled to account for the greater part of the process of brewing, yet it may be observed, even with the assistance of the thermometer, as yet a geometrical exactness, in many respects, has not been attained; but nature, when the interest and necessities of mankind are the object, apparently has supplied our wants, and rectified our defects. In this art, fermentation, when allowed to display itself, corrects all our errors to a considerable latitude, though as yet, of this act, it may be said we scarcely conceive its cause, or properly discern its effects. PART II. THE PRACTICE OF BREWING. Before I enter upon the practical, and indeed most important, part of this work, it will not be improper to give a distinct, though general, view of the different parts it is to consist of. To extract from malt a liquor, which, by the help of fermentation, may acquire the properties of wine, is the general object of the brewer, and the rules of that art are the subject of these sheets. An art truly very simple, if, according to vulgar opinion, it consisted in nothing else than applying warm-water to malt, mashing these together, multiplying the taps at discretion, boiling the extracts with a few hops, suffering the worts to cool, adding yeast to make it ferment, and trusting to time, cellars, and nostrums, for its taste, brightness, and preservation! A few notes and observations, such as are too often found to be foisted under the articles of beer and brewing, in some books of agriculture and others of cookery, might be sufficient, were the place and constitution of the air always the same, the materials and vessels employed entirely similar, and lastly, the malt drinks intended for the same use and time; but, as every one of these particulars is liable to variations, and can be complied with, only by the application of different determinate heats; was the artist to submit himself to loose, vague, and erroneous directions, like those above mentioned, they would only serve to deceive him, and his case would be but little mended, if he trusted to indefinite signs, and insufficient maxims, in his deviation from them.