BOOK VII. 237 



of this powder there are mixed two unciae of yellow litharge, likewise crushed. 

 This mixture is put into a scorifier large enough to hold it, and placed under 

 the muffle of a hot furnace ; when the charge flows like water, which occurs 

 after half an hour, it is taken out of the furnace and poured on to a stone, 

 and when it has hardened it has the appearance of glass, and this is likewise 

 crushed. This powder is sprinkled over any metalliferous ore which does 

 not easily melt when we are assaying it, and it causes the slag to exude. 

 Others, in place of litharge, substitute lead ash, 22 which is .made in the 

 following way : sulphur is thrown into lead which has been melted in a 

 crucible, and it soon becomes covered with a sort of scum ; when this is 

 removed, sulphur is again thrown in, and the skin which forms is again taken 

 off ; this is frequently repeated, in fact until all the lead is turned into 

 powder. There is a powerful flux compound which is made from one uncia 

 each of prepared saltpetre, melted salt, glass-gall, and argol, and one-third 

 of an uncia of litharge and a bes of glass ground to powder ; this flux, being 

 added to an equal weight of ore, liquefies it. A more powerful flux is made by 

 placing together in a pot, smeared on the inside with litharge, equal portions 

 of white argol, common salt, and prepared saltpetre, and these are heated 

 until a white powder is obtained from them, and this is mixed with as much 

 litharge ; one part of this compound is mixed with two parts of the ore which 

 is to be assayed. A still more powerful flux than this is made out of ashes 

 of black lead, saltpetre, orpiment, stibium, and dried lees of the aqua with 

 which gold workers separate gold from silver. The ashes of lead 23 are made from 

 one pound of lead and one pound of sulphur ; the lead is flattened out into 

 sheets by pounding with a hammer, and placed alternately with sulphur in a 

 crucible or pot, and they are heated together until the fire consumes the 

 sulphur and the lead turns to ashes. One libra of crushed saltpetre is mixed 

 with one libra of orpiment similarly ground to powder, and the two are cooked 

 in an iron pan until they liquefy ; they are then poured out, and after cool- 

 ing are again ground to powder. A libra of stibium and a bes of the 

 dried lees (of what ?) are placed alternately in a crucible and heated to the 

 point at which they form a button, which is similarly reduced to powder. 

 A bes of this powder and one libra of the ashes of lead, as well as a libra of 

 powder made out of the saltpetre and orpiment, are mixed together and a 



including Loehneys, Ercker and Cramner, and used even yet. The " powerful flux " would be a 

 reducing, desulphurizing, and an acid flux. The " more powerful " would be a basic flux 

 in which the reducing action of the argols would be largely neutralized by the nitre. The 

 " still more powerful " would be a strongly sulphurizing basic flux, while the " most powerful " 

 would be a still more sulphurizing flux, but it is badly mixed as to its oxidation and basic 

 properties. (See also note 19 on sal arlificiosus). 



22 Lead ash (Cinis Plumbi. Glossary, Pleyasch). This was obviously, from 

 the method of making, an artificial lead sulphide. 



23 Ashes of lead (Nigri plumbi cinis). This, as well as lead ash, was also 

 an artificial lead sulphide. Such substances were highly valued by the Ancients for medicinal 

 purposes. Dioscorides (v, 56) says : " Burned lead (Molybdos cecaumenos) is made in this 

 way : Sprinkle sulphur over some very thinnest lead plates and put them into a new 

 earthen pot, add other layers, putting sulphur between each layer until the pot is full ; set 

 it alight and stir the melted lead with an iron rod until it is entirely reduced to ashes and 

 until none of the lead remains unburned. Then take it off, first stopping up your nose, 

 because the fumes of burnt lead are very injurious. Or burn the lead filings in a pot with 

 sulphur as aforesaid." Pliny (xxxiv., 50) gives much the same directions. 



