BOOK X.

457

and to wash it with warm water. Finally, it is placed in a bowl, and, whendry, the granules or leaves are rubbed against a touchstone at the same timeas a touch-needle, and considered carefully as to whether they be pure oralloyed. If they are not pure enough, the granules or the leaves, togetherwith the cement which attracts silver and copper, are arranged alternatelyin layers in the same manner, and again heated; this is done as often as isnecessary, but the last time it is heated as many hours as are required tocleanse the gold.

Some people add another cement to the granules or leaves. This cementlacks the ingredients of metalliferous origin, such as verdigris and vitriol, forif these are in the cement, the gold usually takes up a little of the base metal;or if it does not do this, it is stained by them. For this reason some veryrightly never make use of cements containing these things, because brickdust and salt alone, especially rock salt, are able to extract all the silver andcopper from the gold and to attract it to themselves.

It is not necessary for coiners to make absolutely pure gold, but to heatit only until such a fineness is obtained as is needed for the gold money whichthey are coining.

The gold is heated, and when it shows the necessary golden yellow colourand is wholly pure, it is melted and made into bars, in which case they areeither prepared by the coiners with chrysocolla, which is called by the Moorsborax, or are prepared with salt of lye made from the ashes of ivy or ofother salty herbs.

The cement which has absorbed silver or copper, after water has beenpoured over it, is dried and crushed, and when mixed with hearth-lead andde-silverized lead, is smelted in the blast furnace. The alloy of silver andlead, or of silver and copper and lead, which flows out, is again melted in thecupellation furnace, in order that the lead and copper may be separated fromthe silver. The silver is finally thoroughly purified in the refining furnace,and in this practical manner there is no silver lost, or only a minute quantity.

There are besides this, certain other cements 20 which part gold fromsilver, composed of sulphur, stibium and other ingredients. One of thesecompounds consists of half an undo, of vitriol dried by the heat of the fireand reduced to powder, a sixth of refined salt, a third of stibium, half a libra

2 “The processes involved by these “other” compounds are difficult to understand,because of the lack of information given as to the method of operation. It might be thoughtthat these were five additional recipes for cementing pastes, but an inspection of theirinternal composition soon dissipates any such assumption, because, apart from the lack ofbrickdust or some other similar necessary ingredient, they all contain more or less sulphur.After describing a preliminary treatment of the bullion by cupellation, the author says :,, . en the silver is sprinkled with two undue of that powdered compound and is

“ Tuf reC *' Afterward it is poured into another crucible .... and violently shaken.

lhe rest is performed according to the process I have already explained.” As he hasalready explained four or five parting processes, it is not very clear to which one this refers,n fact, the whole of this discussion reads as if he were reporting hearsay, for it lacks in everyrespect the infinite detail of his usual descriptions. In any event, if the powder was intro-r C ^ C « lnt0 t ^ le molten bullion, the effect would be to form some silver sulphides in a regulusof different composition depending upon the varied ingredients of different compounds.The enriched bullion was settled out in a “ lump ” and treated “ as I have explained,”which is not clear.