BOOK VII.

251

will be found in the bottom of the cupel. The fire consumes both of thosemetals more quickly if they are heated in that furnace which draws in air. Itis better to cover the upper half of it with a lid, and not only to put on themuffle door, but also to close the window of the muffle door with a piece ofcharcoal, or with a piece of brick. If the copper be such that the silver canonly be separated from it with difficulty, then before it is tested with fire inthe cupel, lead should first be put into the scorifier, and then the copper shouldbe added with a moderate quantity of melted salt, both that the lead mayabsorb the copper and that the copper may be cleansed of the dross whichabounds in it.

Tin which contains silver should not at the beginning of the assay beplaced in a cupel, lest the silver, as often happens, be consumed and convertedinto fumes, together with the tin. As soon as the lead 36 has begun to fumein the scorifier, then add that 36 to it. In this way the lead will take thesilver and the tin will boil and turn into ashes, which may be removed with awooden splinter. The same thing occurs if any alloy is melted in which thereis tin. When the lead has absorbed the silver which was in the tin, then,and not till then, it is heated in the cupel. First place the lead with whichthe silver is mixed, in an iron pan, and stand it on a hot furnace and let itmelt ; afterward pour this lead into a small iron mould, and then beat itout with a hammer on an anvil and make it into leaves in the same way asthe copper. Lastly, place it in the cupel, which assay can be carried out inthe space of half an hour. A great heat is harmful to it, for which reasonthere is no necessity either to cover the half of the furnace with a lid or toclose up its mouth.

The minted metal alloys, which are known as money, are assayed in thefollowing way. The smaller silver coins which have been picked out fromthe bottom and top and sides of a heap are first carefully cleansed ; then, afterthey have been melted in the triangular crucible, they are either resolvedinto granules, or made into thin leaves. As for the large coins which weigha drachma, a slcilicus, half an uncia, or an uncia, beat them into leaves.Then take a bes of the granules, or an equal weight of the leaves, and likewisetake another bes in the same way. Wrap each sample separately in paper,and afterwards place two small pieces of lead in two cupels which have firstbeen heated. The more precious the money is, the smaller portion of leaddo we require for the assay, the more base, the larger is the portion required ;for if a bes of silver is said to contain only half an uncia or one uncia of copper,we add to the bes of granules half an uncia of lead. If it is composed of equalparts of silver and copper, we add an uncia of lead, but if in a bes of copperthere is only half an uncia or one uncia of silver, we add an uncia and a halfof lead. As soon as the lead has begun to fume, put into each cupel one ofthe papers in which is wrapped the sample of silver alloyed with copper, andclose the mouth of the muffle with charcoal. Heat them with a gentle fireuntil all the lead and copper are consumed, for a hot fire by its heat forces the

35 Lead and Tin seem badly mixed in this paragraph.

36 It is not clear what is added.