Replication in laboratory of an experiment reported by Gabriel Plattes, A Discovery of Subterraneall Treasure (1639): “Now for a plaine demonstration [of how mineral ores are generated], let this experiment following be tryed, and I make no question, but that it will satisfie every one that hath an inquisitive disposition. Let there bee had a great retort of glasse, and let the same be halfe filled with brimstone, sea-coale, and as many bituminous and sulphurious subterraneall substances as can bee gotten: then fill the necke thereof halfe full with the most free earth from stones that can be found, but thrust it not in too hard, then let it bee luted, and set in an open furnace to distill with a temperate fire, which may onely kindle the said substances, and if you worke exquisitely, you shall finde the said earth petrified, and turned into a stone: you shall also finde cracks and chinkes in it, filled with the most tenacious, clammy, and viscous parts of the said vapours, which ascended from the subterraneall combustible substances. Wereby it appeareth that the same thing is done by Nature, and that the rocks and craggy mountaines are caused by the vapours of bituminous and sulphurious substances kindled in the bowells of the earth, of which there bee divers so well knowne, that they neede not bee heere mentioned [...]” (pp. 5-7). This experiment is also mentioned in Emerton 1984, p. 249. See also Debus 1961. “Take a peece of the blacke fat earth, which is usually digged up in the west countrey, where there are such a multitude of firre trees covered therewith, and which the people use to cut in the forme of bricks, and to drye them, & so to burne them in stead of coales; use this substance as you did the other earth in the beginning of the booke, to find out the natural cause of rocks, stones, and mettalls, and let it receive the vapours of the cumbustible substances, and you shall find this fat earth hardned into a plaine coale; even as you found the other leane earth hardned into a stone” (p. 50).