In and about the city of London, the most intense cold that has been observed is 14 degrees, and the greatest heat has made the thermometer rise, in the shade, to 89. Within these limits are comprehended all the fermentable degrees, and consequently those necessary for carrying on the process of brewing. If the lowest degree proper for fermentation be 40, and the highest 80, the medium of these two would, at first sight, appear to be the fittest for this purpose; but the internal motion, necessary to carry on fermentation, excites a heat superior to the original state of the must by 10 degrees. Hence, if 60 degrees be the highest eligible heat a fermenting must should arise to, 50 should be the highest for a wort to be let down at, to begin this act; which heat can only be obtained, when that of the air is equal thereto, so that it denotes the highest natural heat for beers and ales to be properly fermented. With regard to the other extreme, or the lowest heat, however cold the air may be, as the worts, which form both beers and ales, gain, by boiling, a degree greatly superior to any allowed of in fermentation, it is constantly in the artist’s power to adapt his worts to a proper state. The brewing season, then, may justly be esteemed all that part of the year in which the medium heat of the day is at or below 50 degrees: this, in our climate, is from the beginning of October to the middle of May, or 32 weeks; the most elegible period of time for brewing all kinds of beers. But, as many incidents often make it necessary to extend these limits, the only time for venturing to comply therewith is, when the medium heat of the season is at 55 degrees; by which, six weeks more may be obtained. But, under these circumstances, the quantity of beer brewed should be less, that the worts may cool more readily, by being thinner spread; and, to gain more time, the brewing is best carried on with two worts only: taking these precautions, and beginning early in the morning, the first wort, by laying long enough in the coolers, will, towards evening, be brought to a heat of 55 degrees. The night, in this season of the year, being generally colder by 10 or 12 degrees than the medium heat of the whole 24 hours, the second worts may be reduced to a cold of 43 degrees: the mean of 55 and 43, being 49 degrees, would be the real heat of the worts in the ton; and with 10 degrees more, (the heat gained by fermentation,) still it would not reach 60 degrees, the highest fermentable heat, beers intended to preserve themselves long should arrive to; but so near would it be to this, and so little is the uniformity of the heat of the air to be relied on, that necessity alone can justify the practice of brewing such drinks, when the heat of the air is so high as 55, consequently, where it exceeds this, it should never be attempted.