Lute may be made divers wayes for this business; for men prepare their Lute several wayes as they please. Some mix with sifted Potters earth, the beaten hairs of Cows, Oxen, Harts, or the chaffe of Barley, Tow, Flocks, Horse dung, and the like, that hold together the clay, and prevent chops, to which they add sometimes sifted sand, if the clay be too fat, beating the mixture together with water, and bringing it to a just consistence. And this is the best mixture, that is not subject to cleaving, yet weak, because in length of time the hair and chaffe are burnt, wherefore the Furnace becomes thin and weak. Many leave out combustible things, and mix Potters clay, and sand together, and temper them with brine, for the making of their Furnaces. And this is the best mixture, because it is not combustible as the other is, neither is it subject to cracking, by reason of the salt: and for this purpose, the brine of fish and salt flesh doth serve, and is very good, because the blood helps the joining of them together: but if the _Caput mortuum_ of vitriol or _Aqua fortis_, being mollifyed, be mixed with Potters clay and sand, you go a better way to work: for this Lute is not at all subject to cracking, but fixed in the fire and permanent. With this Lute are Retorts, and Gourds very well luted, and coated, also the joints of Retorts, and Receivers closed: this being mollifyed with a wet cloth applyed to it, may again be separated, and taken off, as that also with which salt is mixed: but the other Lutes that want salt will not be separated, by reason whereof glasses oftentimes are broken. Wherefore in defect of the _Caput mortuum_ of Vitriol, temper the clay and sand with brine: But many mix the filings of iron, powdered glass, flints, _&c._ but you need not them for the building of the Furnaces, but only for the coating of certain glasses used for separation, and distillation, because the filings of iron being helped with salt, binds, and joins together most strongly. _Of the closing of the Joints, hindering the evaporation of subtle Spirits._