450 BOOK X. 



sulphur, there is weighed out also a sixth of a libra and a sicilicus of 

 copper, if each libra consists either of three-quarters of a libra of silver and 

 a quarter of a libra of copper, or of three-quarters of a libra and a 

 semi-uncia of silver and a sixth of a libra and a semi-uncia of copper. If, 

 however, the silver contains five-sixths of a /ifera of silver and a sixth of a 

 W6ya of copper, or five-sixths of a libra and a semi-uncia of silver and an w«cia 

 and a half of copper, then there are weighed out a quarter of a libra of copper 

 granules. If a libra contains eleven-twelfths of a libra of silver and one uncia 

 of copper, or eleven-twelfths and a semi-uncia of silver and a semi-uncia of 

 copper, then are weighed out a quarter of a libra and a semi-uncia and a 

 sicilicus of copper granules. Lastly, if there is only pure silver, then as much 

 as a third of a libra and a semi-uncia of copper granules are added. Half 

 of these copper granules are added soon afterward to the black-coloured 

 silver granules. The crucible should be tightly covered and smeared over 

 with lute, and placed in a furnace, into which the air is drawn through the 

 draught-holes. As soon as the silver is melted, the crucible is opened, and 

 there is placed in it a heaped ladleful more of granulated copper, and also 

 a heaped ladleful of a powder which consists of equal parts of litharge, of 

 granulated lead, of salt, and of glass-galls ; then the crucible is again covered 

 with the lid. When the copper granules are melted, more are put in, together 

 with the powder, until all have been put in. 



A little of the regulus is taken from the crucible, but not from the gold 

 lump which has settled at the bottom, and a drachma of it is put into each of 

 the cupels, which contain an uncia of molten lead ; there should be many 

 of these cupels. In this way half a drachma of silver is made. As soon as 

 the lead and copper have been separated from the silver, a third of it is 

 thrown into a glass ampulla, and aqua valens is poured over it. By this 

 method is shown whether the sulphur has parted aU the gold from the silver, 

 or not. If one wishes to know the size of the gold lump which has settled 

 at the bottom of the crucible, an iron rod moistened with water is covered 

 with chalk, and when the rod is dry it is pushed down straight into the 

 crucible, and the rod remains bright to the height of the gold lump ; the 

 remaining part of the rod is coloured black by the regulus, which adheres to 

 the rod if it is not quickly removed. 



If when the rod has been extracted the gold is observed to be 

 satisfactorily parted from the silver, the regulus is poured out, the gold 

 button is taken out of the crucible, and in some clean place the regulus is 

 chipped off from it, although it usually flies apart. The lump itself is reduced 

 to granules, and for every libra of this gold they weigh out a quarter of a libra 

 each of crushed sulphur and of granular copper, and all are placed together 

 in an earthen crucible, not into a pot. When they are melted, in order that 

 the gold may more quickly settle at the bottom, the powder which I have 

 mentioned is added. 



Although minute particles of gold appear to scintillate in the regulus 

 of copper and silver, yet if aU that are in a libra do not weigh as much as a 

 single sesterce, then the sulphur has satisfactorily parted the gold from the 



