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BOOK IX.

Others build a hollow vaulted chamber, of which the paved floor is madeconcave toward the centre. Inside the thick walls of the chamber are thefurnaces. The doors through which the wood is put are in the outer part of thesame wall. They place the pots in the furnaces and fill them with crushedore, then they cement the pots and the furnaces on all sides with lute, so thatnone of the vapour may escape from them, and there is no entrance to the

A—Enclosed chamber. B— Door. C— Little windows. D—Mouths through thewalls. E—Furnace in the enclosed chamber. F—Pots.

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furnaces except through their mouths. Between the dome and the pavedfloor they arrange green trees, then they close the door and the little windows,and cover them on all sides with moss and lute, so that none of the quick-silver can exhale from the chamber. After the wood has been kindled the

possible however, that it was written late in the 15th Century (see Appendix B). He describesthe preparation of the metal from the crude ore, both by roasting and reduction from the oxidewith argol and saltpetre, and also by fusing with metallic iron. While the first descrip-tion of these methods is usually attributed to Valentine, it may be pointed out that inthe Probierbuchlein (1500) as well as in Agricola the separation of silver from iron byantimony sulphide implies the same reaction, and the separation of silver and gold withantimony sulphide, often attributed to Valentine, is repeatedly set out in the Probier-buchlein and in De Re Metallica. Biringuccio (1540) has nothing of importance to say as tothe treatment of antimonial ores, but mentions it as an alloy for bell-metal, which wouldimply the metal.