BOOK IX. 397 



and a quarter of a libra of argol ; they should be melted in a crucible on a 

 slow fire for three hours, then the alloy is put into molten silver that it 

 may melt more rapidly. Or a libra of the same crude gold, crushed up, is 

 mixed together with half a libra of stibium likewise crushed, and put 

 into a crucible with half an uncia of copper fiUngs, and heated until they 

 melt, then a sixth part of granulated lead is thrown into the same crucible. 

 As soon as the mixture emits an odour, iron-fihngs are added to it, or if these 

 are not at hand, iron hammer-scales, for both of these break the strength of 

 the stibium. When the fire consumes it, not alone with it is some strength 

 of the stibium consumed, but some particles of gold and also of silver, if it 

 be mixed with the gold''®. When the button has been taken out of the 

 crucible and cooled, it is melted in a cupel, first until the antimony is exhaled, 

 and thereafter until the lead is separated from it. 



Crushed pyrites which contains gold is smelted in the same way ; it 

 and the stibium should be of equal weight, and in truth the gold may be 

 made from them in a number of different ways'". One part of crushed 

 material is mixed with six parts of copper, one part of sulphur, half a part of 

 salt, and they are all placed in a pot and over them is poured wine distilled 

 by heating liquid argol in an ampulla. The pot is covered and smeared 

 over with lute and is put in a hot place, so that the mixture moistened with 

 wine may dry for the space of six days, then it is heated for three hours over 

 a gentle fire that it may combine more rapidly with the lead. Finally it is put 

 into a cupel and the gold is separated from the lead'^. 



Or else one libra of the concentrates from washing pyrites, or other stones 

 to which gold adheres, is mixed with half a libra of salt, half a libra of argol, 

 a third of a libra of glass-galls, a sixth of a libra of gold or silver slags, and a 

 siciUcus of copper. The crucible into which these are put, after it has been 

 covered with a lid, is sealed with lute and placed in a small furnace that is 

 provided with small holes through which the air is drawn in, and then it is 

 heated until it turns red and the substances put in have alloyed ; this should 

 take place within four or five hours. The alloy having cooled, it is again 

 crushed to powder and a pound of litharge is added to it ; then it is heated 

 again in another crucible until it melts. The button is taken out, purged of 

 slag, and placed in a cupel, where the gold is separated from the lead. 



*^Quod cum ignis consumit non modo una cum eo, quae ipsius stibii vis est, aliqua auri 

 particula, sed etiam argenti, si cum auro fuerit permistum, consumitur. The meaning is by no 

 means clear. On p. 451 is set out the old method of parting silver from gold with antimony 

 sulphide, of which this may be a variation. The silver combines with sulphur, and the reduced 

 antimony forms an alloy with the gold. The added iron and copper would also combine with 

 the sulphur from the antimony sulphide, and no doubt assist by increasing the amount of free 

 collecting agent and by increasing the volume of the matte. (See note 17, p. 451.) 



'"There follow eight different methods of treating crude bullion or rich concentrates. 

 In a general way three methods are involved, — ist, reduction with lead or antimony, and 

 cupellation ; 2nd, reduction with silver, and separation with nitric acid ; 3rd, reduction 

 with lead and silver, followed by cupellation and parting with nitric acid. The use of sulphur 

 or antimony sulphide would tend to part out a certain amount of silver, and thus obtain 

 fairly pure bulHon upon cupellation. But the introduction of copper could only result 

 deleteriously, except that it is usually accompanied by sulphur in some form, and would thus 

 probably pass off harmlessly as a matte carrying silver. (See note 33 below.) 



'^It is not very clear where this lead comes from. Should it be antimony ? The 

 German translation gives this as " silver." 



28 



