Worts are composed of oils, salts, water, and perhaps some small portion of earth, from both the malt and hops. Oils are capable of receiving a degree of heat much superior to salts, and these again surpass, in this respect, the power of water. Before a wort can be supposed to have received the whole of the fire it can admit of, such a degree of heat must arise, as will be in a proportion to the quantity of the oils, the salts, and the water. When this happens, the wort may be said to be intimately mixed, and to have but one taste. The fire, made fiercer, would not increase the heat, or more exactly blend together the constituent parts; this purpose once obtained, the boiling of the wort is completed. It follows from thence, that some worts will boil sooner than others, receive their heat in a less time, and be saturated with less fire; but, as it is impossible, and, indeed, unnecessary, to estimate exactly the quantities of oils, salts, and water contained in each different wort, it is out of our power previously to fix, for any one, the degree of heat it is capable of. This renders the thermometer in this case useless, and obliges us to depend entirely on experiment, and to observe the signs which accompany the act of ebullition. Fire, as before has been mentioned, when acting upon bodies, endeavours to make its way through them in right lines. A wort set to boil, makes a resistance to the effort of fire, in proportion to the different parts it is composed of. The watery particles are, it is imagined, the first, which are saturated with fire, and becoming lighter in this manner, endeavour to rise above the whole. The salts are next, and last of all the oils. From this struggle proceeds the noise heard when the wort first boils, which proves how violently it is agitated, before the different principles are blended one with another. While this vehement ebullition lasts, we may be sure that the wort is not intimately mixed, but when the fire has penetrated and united the different parts, the noise abates, the wort boils smoother, the steam, instead of clouding promiscuously as it did at first round the top of the copper, rises more upright, in consequence of the fire passing freely in direct lines through the drink, and when the fierceness of it drives any part of the drink from the body of the wort, the part so separated ascends perpendicularly. Such are the signs by which we may be satisfied the first wort, or the strongest part of the extracts, has been so affected by the fire, as to become nearly of one taste. If, at this time, it is turned out of the copper, it appears pellucid, and forms no considerable sediment.