By the foregoing table, it is seen that my great copper holds nearly nine barrels of water to brass, and as the difference of the volume between boiling worts, of most denominations, and cold water, is nearly as 7 to 9, the quantity it will yield of boiling worts will be but seven barrels. The diameter of this copper, just above brass, is sixty-eight inches, at a medium, and at that mean it holds twelve gallons seven pints of cold water, or nearly eleven gallons of boiling worts, upon an inch. Hops macerated, by being twice boiled, take up for every six pound weight a volume, in the copper, equal to four gallons and a half of water, or a _pin_. In a copper, the gauges of which have just been set down, it is required to know what number of inches a length of twenty-four barrels must go out at, with fifteen pounds of hops, the guile of beer to be brewed at two worts. 24 Barrels, length of beer. 14 Barrels, for two full brass, ---- 10 34 Numbers of gallons to a barrel accounted by the excise, out of the bills of mortality. ---- 40 Hops twice put in 15lb. is 30 30 ---- ---- 6lb. [ 30 340 ---- Gallons of 22 5 boiling wort ---- Equal to gallons 4-1/2 upon an inch 11 [362 ---- ---- 22 ---- 33 Inches above brass, the two worts to go out together. When three worts are boiled, the amount of three full brasses must be deducted from the length; and as the hops go into the copper three times, they become more macerated, and take up much less room. The proportion is then nearly thirteen or fourteen pounds of hops for each four gallons and a half. Thus in coppers, which have never been tried or used, we are able, by the gauges alone, to determine our lengths; but, as their circumferences are not always exact, and the worts are of very different strengths, we should never neglect such trials as may bring us nearer to accuracy and truth. SECTION VII. _OF BOILING._ It has been a question, whether boiling is necessary to a wort; but as hops are of a resinous quality, the whole of their virtues are not yielded by extraction; decoction or boiling is as needful as the plant itself, and is, together with extraction and fermentation, productive of that uniformity of taste in the compound, which constitutes good beer.