Note 19 — BOOK XI.

[Pg 522][19] The first instance given, of 44 centumpondia (3,109 lbs.) lead and one centumpondium (70.6 lbs.) copper, would indicate that the liquated lead contained 2.2% copper. The second, of 46 centumpondia (3,250 lbs.) lead and 11/2 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 110 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.