The thermometer teaches us that the heat of boiling water is equal to 212 degrees, and by calculation we may know what quantity of cold water is necessary to bring it to any degree we choose; so, notwithstanding the instrument cannot be used in large vessels, where the water is heating, yet, by the power of numbers, the heat may be ascertained with the greatest accuracy. The rule is this: multiply 212, the heat of boiling water, by the number of barrels of water thus heated, (suppose 22) and the number of barrels of cold water to be added to the former, (suppose 10,) by the heat of the air at eight o’clock, (suppose 50,) add these two products together, and divide by the sum of the barrels; the quotient shews the degree of heat of the water mixed together. 212 heat of boiling water. 22 barrels to be made to boil. ---- 424 50 deg. heat of air at eight. 424 10 barrels of cold water. ---- --- 22 4664 500 10 500 -- ---- sum 32) 5164(161⅓ degrees will be the heat of the water of barrels 32 when mixed together. ---- 196 192 ---- 44 32 ---- 12 The calculation may be extended to three or more bodies, provided they be brought to the same denomination. Suppose 32 barrels of water to be used where there is a grist of 20 quarters of malt, if these 20 quarters of malt are of a volume or bulk equal to 11 barrels of water, and the malt, by having lain exposed to the air, is of the same degree of heat with the air, in order to know the heat of the mash, the calculation must be thus continued. 161⅓ heat of water 50 degrees of heat of malt 32 barrels of water 11 barrels, volume of malt ---- --- 333 550 483 ---- 32 water 5163 11 malt 550 -- ---- 43 ) 5713 (132 degrees, which will be the heat of 43 the mash. ---- 141 129 ---- 123 86 ---- 37 We shall meet hereafter with some incidents, which occasion a difference in the calculations made for the purpose of brewing, but of these particular mention will be made in the practical part.