If therefore wee intend to immitate nature, we must needes haue such a furnace like vnto the Mountaines, not in greatnesse, but in continual heate, so that the fire put in, when it ascendeth, may finde no vent: but that the heat may beat vpon the vessell being close shutte, containing in it the matter of the stone: which vessell must be round, with a small necke, made of glasse or some earth, representing the nature or close knitting togither of glasse: the mouth whereof must be signed or sealed with a couering of the same matter, or with lute. And as in the mynes, y^e heat doth not immediatly touch the matter of Sulphur and Argent-uiue, because the earth of the mountain cõmenth euery where between: So this fire must not immediatly touch the vessell, containing the matter of the foresaide things in it, but it must be put into another vessell, shut close in the like manner, that so the temperate heate may touch the matter aboue and beneath, and where ere it be, more aptly and fitly: wherevpon _Aristotle_ sayth, in the light of lights, that _Mercurie_ is to be cõcocted in a threefold vessell, and that the vessell must bee of most hard Glasse, or (which is better) of earth possessing the nature of Glasse. CHAP. VI. _Of the accidentall and essentiall colours appearing in the worke._ The matter of the stone thus ended, thou shalt knowe the certaine maner of working, by what maner and regiment, the stone is often chaunged in decoction into diuerse colours. Wherupon one saith, So many colours, so many names. According to the diuerse colours appearing in the worke, the names likewise were varied by the Philosophers: whereon, in the first operation of our stone, it is called putrifaction, and our stone is made blacke: whereof one saith, When thou findest it blacke, know that in that blacknesse whitenesse is hidden, and thou must extract the same from his most subtile blacknes. But after putrefaction it waxeth red, not with a true rednesse, of which one saith: It is often red, and often of a citrine colour, it often melteth, and is often coagulated, before true whitenesse. And it dissolueth it selfe, it coagulateth it selfe, it putrifieth it selfe, it coloureth it self, it mortifieth it selfe, it quickneth it selfe, it maketh it selfe blacke, it maketh it selfe white, it maketh it selfe red. It is also greene; whereon another sayth, Concoct, it till it appeare greene vnto thee, and that is the soule. And another, Know, that in that greene his soule beareth dominion. There appeares also before whitenesse the peacocks colour, whereon one saith thus. Know thou that al the colours in the world, or y^t may be imagined, appeare before whitenesse, and afterward true whitenesse followeth. Whereof one sayth: When it hath bin decocted pure and clean, that it shineth like the eyes of fishes, then are wee to expect his vtilitie, and by that time the stone is congealed rounde. And another sayth: When thou shalt finde whitenesse