January 1 } July 1 } to 15 } 35 to 15 } 60 to 31 } 35 to 31 } 60 February 1 } August 1 } to 14 } 35 to 15 } 60 to 28 } 40 to 31 } 60 March 1 } Septemb. 1 } to 15 } 40 to 15 } 55 to 31 } 40 to 30 } 55 April 1 } October 1 } to 15 } 45 to 15 } 50 to 30 } 45 to 31 } 50 May 1 } Novemb. 1 } to 15 } 50 to 15 } 45 to 31 } 50 to 30 } 40 June 1 } December 1 } to 15 } 60 to 15 } 40 to 30 } 60 to 31 } 35 As nothing is so inconstant as the heat of the air, we are not to be surprised when it deviates from the progression specified in the table. The flowing water used in the brewery, at the coldest seasons, we have fixed at 35 degrees, and the highest heat in the air, to carry on the process for beers brewed for long keeping, at 55 degrees. The length proper to be drawn, or the quantity of beer to be made from each quarter of malt being fixed, the brewer, at any time, has it in his power to make calculations for brewings, supposing the mean heat of the air to be at 35, at 40, at 45, at 50 and even at any degree of heat whatever, so as never to be unprovided for any season. Water, being a body more dense than air, requires some time to receive the impressions either of heat or cold, for which reason the medium heat of the shade of the preceding day, will most conveniently govern this part of the process, unless some very extraordinary change should happen in the atmosphere. This must make the business of the artist, in this respect, very easy, as, in the course of his practice, he will have only to correct the little changes that occasional incidents give rise to; and the calculations will answer all his purposes so long as the lengths of beer to be brewed from the same quantity of malt remain unaltered, and with very little variation and trouble, when the coppers employed, by being changed, are of different dimensions. The best method to know the true heat of cold water, would be to keep a very accurate and distinct thermometer, in the liquor back; but as this, in every place, is not to be expected, and inaccuracies must arise from a change in the air, to prevent their consequences in practice, we must have recourse to experience. This has taught us that a difference of 8 degrees, between the actual heat of the water, and that from which the brewing was computed, will produce, in the first extract, a difference of four degrees.