BOOK IX.

397

and a quarter of a libra of argol ; they should be melted in a crucible on aslow fire for three hours, then the alloy is put into molten silver that itmay melt more rapidly. Or a libra of the same crude gold, crushed up, ismixed together with half a libra of stibium likewise crushed, and putinto a crucible with half an uncia of copper filings, and heated until theymelt, then a sixth part of granulated lead is thrown into the same crucible.As soon as the mixture emits an odour, iron-filings are added to it, or if theseare not at hand, iron hammer-scales, for both of these break the strength ofthe stibium. When the fire consumes it, not alone with it is some strengthof the stibium consumed, but some particles of gold and also of silver, if itbe mixed with the gold 29 . When the button has been taken out of thecrucible 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 ; itand the stibium should be of equal weight, and in truth the gold may bemade from them in a number of different ways 30 . One part of crushedmaterial is mixed with six parts of copper, one part of sulphur, half a part ofsalt, and they are all placed in a pot and over them is poured wine distilledby heating liquid argol in an ampulla. The pot is covered and smearedover with lute and is put in a hot place, so that the mixture moistened withwine may dry for the space of six days, then it is heated for three hours overa gentle fire that it may combine more rapidly with the lead. Finally it is putinto a cupel and the gold is separated from the lead 31 .

Or else one libra of the concentrates from washing pyrites, or other stonesto 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 asicilicus of copper. The crucible into which these are put, after it has beencovered with a fid, is sealed with lute and placed in a small furnace that isprovided with small holes through which the air is drawn in, and then it isheated until it turns red and the substances put in have alloyed ; this shouldtake place within four or five hours. The alloy having cooled, it is againcrushed to powder and a pound of litharge is added to it ; then it is heatedagain in another crucible until it melts. The button is taken out, purged ofslag, and placed in a cupel, where the gold is separated from the lead.

ZB Quod cum ignis consumit non modo una cum eo, quae ipsius stibii vis est, aliqua auriparticula, sed etiam argenti, si cum auro fuerit permistum , consumitur. The meaning is by nomeans clear. On p. 451 is set out the old method of parting silver from gold with antimonysulphide,, of which this may be a variation. The silver combines with sulphur, and the reducedantimony forms an alloy with the gold. The added iron and copper would also combine withthe sulphur from the antimony sulphide, and no doubt assist by increasing the amount of freecollecting agent and by increasing the volume of the matte. (See note 17, p. 451.)

3 “There follow eight different methods of treating crude bullion or rich concentrates.In a general way three methods are involved,—1st, reduction with lead or antimony, andcupellation ; 2nd, reduction with silver, and separation with nitric acid ; 3rd, reductionwith lead and silver, followed by cupellation and parting with nitric acid. The use of sulphuror antimony sulphide would tend to part out a certain amount of silver, and thus obtainfairly pure bullion upon cupellation. But the introduction of copper could only resultdeleteriously, except that it is usually accompanied by sulphur in some form, and would thusprobably pass off harmlessly as a matte carrying silver. (See note 33 below.)

81 It is not very clear where this lead comes from. Should it be antimony ? TheGerman translation gives this as " silver.”

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