A description of new philosophical furnaces, or A new art of distilling, divided into five parts. Whereunto is added a description of the tincture of gold, or the true aurum potabile; also, the first part of the mineral work. Set forth and published for the sakes of them that are studious of the truth. / By John Rudolph Glauber. Set forth in English, by J.F. D.M.

A Lute for the erecting of Furnaces.

LUte may be made divers wayes for this businesse; 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 adde sometimes sifted sand, if the clay be too fat, beating the mixture together with water, and bringing it to a just consistency. 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 pur∣pose the brine of fish and salt flesh doth serve, and is very good, because the bloud helps the joining of them together: but

if the caput mortuum of vitriol or aqua fortis, being mollified, be mixed with potters clay and sand, you goe 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 goards very well luted, and coated, also the joints of retorts, and receivers closed: this being mollified 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 mixe 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 certaine glasses used for separa∣tion, and distillation, because the filings of iron being helped with salt binds and joins together most strongly.