510 



BOOK XL 



If a centumpondium of copper contains two librae and a bes of silver, and 

 the lead a third of a libra and a semi-uncia, there will be in each liquation 

 cake one and a half librae and a semi-uncia, and a little more than a sicilicus 

 of silver. In the exhausted liquation cakes there remain a third of a Zi6r« 

 and a semi-uncia of silver. 



If there be in the copper only a minute proportion of silver, it cannot be 

 separated easily until it has been re-melted in other furnaces, so that in 

 the " bottoms " there remains more silver and in the " tops " less.^^ This 



-Furnace. B — Forehearth 



Dipping-Pot. 



furnace, vaulted with unbaked bricks, is similar to an oven, and also to the 

 cupellation furnace, in which the lead is separated from silver, which I described 

 in the last book. The crucible is made of ashes, in the same manner as 



^^In this enrichment of copper by the " settling " of the silver in the molten mass the 

 original copper ran, in the two cases given, 5o ozs. 15 dwts and 85 ozs. i dwt. per ton. The 

 whole charge weighed 2,685 lbs., and contained in the second case 114 ozs. Troy, omitting 

 fractions. On melting, 1,060 lbs. were drawn off as " tops," containing 24 ozs. of silver, or 

 running 45 ozs. per ton, and there remained 1,625 lbs. of "bottoms," containing 90 ozs. of 

 silver, or averaging no ozs. per ton. It will be noticed later on in the description of making 

 liquation cakes from these copper bottoms, that the author alters the value from one-third 

 librae, a semi-uncia and a drachma per centumpondium to one-third of a libra, i.e., from no ozs. 

 to 97 ozs. 4 dwts. per ton. In the Glossary this furnace is described as a spleisofen, i.e., a 

 refining hearth. 



