Bacon, Roger - The Mirror of Alchemy – Chapter 05
Type of Spiritual Experience
A description of the experience
Of the quality of the Vessel and Furnace.
The means and manner of working, we have already determined: now we are to speak of the Vessel and Furnace, in what sort, and of what things they must be made. Whereas nature by a natural fire decocts the metals in the Mines, she denies the like decoction to be made without a vessel fit for it. And if we propose to imitate nature in concocting, wherefore do we reject her vessel!
Let us first of all therefore, see in what place the generation of metals is made. It does evidently appear in the places of Minerals, that in the bottom of the mountain there is heat continually alike, the nature whereof is always to ascend, and in the ascension it always dries up, and coagulates the thicker or grosser water hidden in the belly, or veins of the earth, or mountain, into Argent-vive.
And if the mineral fatness of the same place arising out of the earth, be gathered warm together in the veins of the earth, it runs through the mountain, and becomes Sulphur. And as a man may see in the foresaid veins of that place, that Sulphur engendered of the fatness of the earth (as is before touched) meets with the Argent-vive (as it is also written) in the veins of the earth, and begets the thickness of the mineral water. There, through the continual equal heat in the mountain, in long process of time diverse metals are engendered, according to the diversity of the place. And in these Mineral places, you shall find a continual heat.
For this cause we are of right to note, that the external mineral mountain is everywhere shut up within itself, and stony: for if the heat might issue out, there should never be engendered any metal. If therefore we intend to immitate nature, we must needs have such a furnace like unto the Mountains, not in greatness, but in continual heat, so that the fire put in, when it ascends, may find no vent: but that the heat may beat upon the vessel being close shut, containing in it the matter of the stone: which vessel must be round, with a small neck, made of glass or some earth, representing the nature or close knitting together of glass: the mouth whereof must be signed or sealed with a covering of the same matter, or with lute. And as in the mines, the heat does not immediately touch the matter of Sulphur and Argent-vive, because the earth of the mountain comes everywhere between: So this fire must not immediately touch the vessel, containing the matter of the aforesaid things in it, but it must be put into another vessel, shut closed in the like manner, that so the temperate heat may touch the matter above and beneath, and where ever it be, more aptly and fitly: whereupon Aristotle says, in the light of lights, that Mercury is to be concocted in a three-fold vessel, and that the vessel must be of most hard Glass, or (which is better) of Earth possessing the nature of Glass.