BOOK IX. 433 



Bismuth 59 ore, free from every kind of silver, is smelted by various 

 methods. First a small pit is dug in the dry ground ; into this pulverised 

 charcoal is thrown and tamped in, and then it is dried with burning charcoal. 

 Afterward, thick dry pieces of beech wood are placed over the pit, and the 

 bismuth ore is thrown on it. As soon as the kindled wood burns, the heated 

 ore drips with bismuth, which runs down into the pit, from which when cooled 

 the cakes are removed. Because pieces of burnt wood, or often charcoal 

 and occasionally slag, drop into the bismuth which collects in the pit, and 

 make it impure, it is put back into another kind of crucible to be melted, 

 so that pure cakes may be made. There are some who, bearing these things 

 in mind, dig a pit on a sloping place and below it put a forehearth, into 

 which the bismuth continually flows, and thus remains clean ; then they 

 take it out with ladles and pour it into iron pans lined inside with lute, and 

 make cakes of it. They cover such pits with flat stones, whose joints are 

 besmeared with a lute of mixed dust and crushed charcoal, lest the joints 

 should absorb the molten bismuth. Another method is to put the ore in 

 troughs made of fir-wood and placed on sloping ground ; they place small 

 firewood over it, kindling it when a gentle wind blows, and thus the ore is 

 heated. In this manner the bismuth melts and runs down from the troughs 

 into a pit below, while there remains slag, or stones, which are of a yellow 

 colour, as is also the wood laid across the pit. These are also sold. 



' through." Pliny (xxxin, 41) : " There has been discovered a way of extracting hydrargyros 



' from the inferior minium as a substitute for quicksilver, as mentioned. There are two 



' methods : either by pounding minium and vinegar in a brass mortar with a brass pestle, 



' or else by putting minium into a flat earthen dish covered with a lid, well luted with potter's 



' clay. This is set in an iron pan and a fire is then lighted under the pan, and continually 



' blown by a bellows. The perspiration collects on the lid and is wiped off and is like silver 



' in colour and as liquid as water." Pliny is somewhat confused over the minium or the 



text is corrupt, for this should be the genuine minium of Roman times. The methods of 



condensation on the leaves of branches placed in a chamber, of condensing in ashes placed 



over the mouth of the lower pot, and of distilling in a retort, are referred to by Biringuccio 



(A.D. 1540), but with no detail. 



"'Most of these methods depend upon simple liquation of native bismuth. The 



sulphides, oxides, etc., could not be obtained without fusing in a furnace with appropriate 



de-sulphurizing or reducing agents, to which Agricola dimly refers. In Bermannus (p. 439), 



he says : " Bermannus. I will show you another kind of mineral which is numbered 



' amongst metals, but appears to me to have been unknown to the Ancients ; we call it 



' bisemutum. Naevius. Then in your opinion there are more kinds of metals than the 



' seven commonly believed ? Bermannus. More, I consider ; for this which just now I 



' said we called bisemutum, cannot correctly be called plumbum candidum (tin) nor nigrum 



' (lead), but is different from both, and is a third one. Plumbum candidum is whiter and 



' plumbum nigrum is darker, as you see. Naevius. We see that this is of the colour of 



' galena. Ancon. How then can bisemutum, as you call it, be distinguished from galena ? 



' Bermannus. Easily ; when you take it in your hands it stains them with black unless it 



' is quite hard. The hard kind is not friable like galena, but can be cut. It is blacker than 



' the kind of crude silver which we say is almost the colour of lead, and thus is different 



' from both. Indeed, it not rarely contains some silver. It generally shows that there is 



' silver beneath the place where it is found, and because of this our miners are accustomed 



' to call it the ' roof of silver.' They are wont to roast this mineral, and from the better 



' part they make metal ; from the poorer part they make a pigment of a kind not to be 



' despised." This pigment was cobalt blue (see note on p. 112), indicating a considerable 



confusion of these minerals. This quotation is the first description of bismuth, and the above 



text the first description of bismuth treatment. There is, however, bare mention of the 



mineral earlier, in the following single line from the Probierbuchlein (p. i) : " Jupiter (con- 



" trols) the ores of tin and wismundt." And it is noted in the Nutliche Bergbuchlein in 



association with silver (see Appendix B). 



