The expected quantities, or lengths of beer and ale, can only be found by determining at what height in the copper the worts must be when turned out.

Brewers have several methods of expressing to what part they would have the worts reduced by boiling. Brass, is the technical appellation for the upper rim of the copper; it is a fixed point, from which the estimation generally takes place, either by inches, or by the nails, which rivet the parts of the copper together. These last are not very equal, either in the breadth of their heads, or their distances from each other. Inches then, though not specified on the copper, but determined by the application of a gauge, on which they are marked, claim the preference. The necessity of coppers being gauged, and the contents of what they contain on every inch, both above and below brass, must appear in a stronger light, the nearer we bring the art to exactness. The following tables will shew the most useful manner in which I conceive this gauging should be specified.

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.

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.