522 



BOOK XI. 



is in the copper is mixed with the remainder of silver ; the copper itself, 

 equally with the lead, wiU be changed partly into litharge and partly into 

 hearth-lead.^* The silver-lead alloy which does not melt is taken from the 

 margin of the crucible with a hooked bar. 



The work of " drying " is distributed into four operations, which are 

 performed in four days. On the first — as hkewise on the other three days — the 

 master begins at the fourth hour of the morning, and with his assistant chips 



A — Cakes. B — Hammer. 



off the stalactites from the exhausted hquation cakes. They then carry the 

 cakes to the furnace, and put the stalactites upon the heap of liquation 

 thorns. The head of the chipping hammer is three palms and as many digits 



**The first instance given, of 44 centutnpondia (3,109 lbs.) lead and one centum fondium 

 (70.6 lbs.) copper, would indicate that the liquated lead contained 2.2% copper. The second, 

 of 46 centutnpondia (3,250 lbs.) lead and ij centumpondia copper (106 lbs.), would indicate 3% 

 copper; and in the third, 120 centumpondia (8,478 lbs.) lead and six copper (424 lbs.) would show 

 4.76% copper. This charge of 120 centumpondia in the cupellation furnace would normally 

 make more than no centumpondia of litharge and 30 of hearth-lead, i.e., saturated furnace 

 bottoms. The copper would be largely found in the silver-lead " which does not melt," at the 

 margin of the crucible. These skimmings are afterward referred to as " thorns." It is difficult 

 to understand what is meant by the expression that the silver which is in the copper is mixed 

 with the remaining (reliquo) silver. The coppery skimmings from the cupellation furnace are 

 referred to again in Note 28, p. 539. 



