BOOK XI. 513 



argentiferous lead, in each centumpondium of which there is an uncia and a 

 drachma of silver, or a total of ten unciae less four drachmae. Of the liquation 

 thorns there remain three centumpondia, in each centumpondium of which 

 there are three sicilici of silver ; and there remain four centumpondia of 

 exhausted liquation cakes, each centumpondium of which contains a semi- 

 uncia or four and a half drachmae. Inasmuch as in a centumpondium of copper 

 " bottoms " there is a third of a libra and a semi-uncia of silver, in five of those 

 cakes there must be more than one and a half unciae and half a drachma of 

 silver. 



Then, again, from another two and a half centumpondia of copper 

 " bottoms," together with eleven centumpondia of lead, four liquation cakes 

 are made. If in each centumpondium of copper there was a third of a libra of 

 silver, there would be in the whole of the centumpondia of base metal five- 

 sixths of a libra of the precious metal. To this copper is added eight centum- 

 pondia of poor argentiferous lead, each centumpondium of which contains an 

 uncia and a drachma of silver, or a total of three-quarters of a libra of silver. 

 There is also added three centumpondia of de-silverized lead, in each centum- 

 pondium of which there is a drachma of silver. Therefore, four liquation 

 cakes contain a total of a libra, seven unciae, a sicilicus and a drachma of silver ; 

 thus each centumpondium of lead, when it has been liquated from the copper, 

 contains an uncia and a half and a sicilicus of silver, which alloy we call 

 "medium" silver-lead. 



Then, again, from another two and a half centumpondia of copper 

 " bottoms," together with eleven centumpondia of lead, they make four 

 liquation cakes. If in each centumpondium of copper there were likewise a 

 third of a libra of silver, there will be in all the weight of the base metal five- 

 sixths of a libra of the precious metal. To this is added nine centumpondia 

 of medium silver-lead, each centumpondium of which contains an uncia and 

 a half and a sicilicus of silver ; or a total of a libra and a quarter and a semi- 

 uncia and a sicilicus of silver. And likewise they add two centumpondia of 

 poor silver-lead, in each of which there is an uncia and a drachma of silver. 

 Therefore the four liquation cakes contain two and a third librae of silver. 

 Each centumpondium of lead, when it has been liquated from the copper, 

 contains a sixth of a libra and a semi-uncia and a drachma of silver. This 

 alloy we call "rich" silver-lead; it is carried to the cupellation furnace, 

 in which lead is separated from silver. I have now mentioned in how many 

 ways copper containing various proportions of silver is alloyed with lead, 

 and how they are melted together in the furnace and run into the casting pan. 



Now I will speak of the method by which lead is liquated from copper 

 simultaneously with the silver. The liquation cakes are raised from the 

 ground with the crane, and placed on the copper plates of the furnaces. The 

 hook of the chain let down from the arm of the crane, is inserted in a 

 ring of the tongs, one jaw of which has a tooth ; a ring is engaged in each 

 of the handles of the tongs, and these two rings are engaged in a third, in 

 which the hook of the chain is inserted. The tooth on the one jaw of the 

 tongs is struck by a hammer, and driven into the hole in the cake, at the point 



