oxide form by roasting below 800C using domestic fire, charcoal or dry wood. This is done easily as lead melts at 327C. Lead oxide (PbO) is the oxide form of galena which reacts with the unroasted form lead sulfide (PbS) to form lead (Pb) and sulfur dioxide (SO2). Details on Roman lead smelting have not been published even though open hearths were found in the Mendips by Rahtz and Boon. These remains contained smelted and unsmelted ores. The remains of first-century smelting were found in Pentre, Ffwrndan. Although this discovery was valuable, reconstruction of the remains were impossible due to damage. An extracted ore from the site had a lead content of 3 oz. 5 dwt. per ton and another piece contained 9 oz. 16 dwt per ton of lead. Silver extraction The most important use of lead was the extraction of silver. Lead and silver were often found together in the form of galena, an abundant lead ore. Galena is mined in the form of cubes and concentrated by removing the ore-bearing rocks. It is often recognized by its high density and dark colour. The Roman economy was based on silver, as the majority of higher value coins were minted from the precious metal. British ores found in Laurion, Greece had a low silver content compared to the ores mined from other locations. The Romans used the term 'British silver' for these lead mines. The process of extraction, cupellation, was fairly simple. First, the ore was smelted until the lead, which contained the silver, separated from the rock. The lead was removed, and further heated up to 1100° Celsius using hand bellows. At this point, the silver was separated from the lead (the lead, in the form of litharge, was either blown off the molten surface or absorbed into bone ash crucibles; the litharge was re-smelted to recover the lead), and was put into moulds which, when cooled, would form ingots that were to be sent all over the Roman Empire for minting. Silchester, Wroxeter, and Hengisbury Head were known locations for Roman cupellation remains. When inflation took hold in the third century A.D. and official coins began to be minted made of bronze with a silver wash, two counterfeit mints appeared in Somerset - one on the Polden Hills just south of the Mendips, and the other at Whitchurch, Bristol to the north. These mints, using Mendip silver,