Note 20 — BOOK X.

[Pg 457][20] 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 thought that these were five additional recipes for cementing pastes, but an inspection of their internal composition soon dissipates any such assumption, because, apart from the lack of brickdust 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: "Then the silver is sprinkled with two unciae of that powdered compound and is stirred. Afterward it is poured into another crucible ... and violently shaken. The rest is performed according to the process I have already explained." As he has already explained four or five parting processes, it is not very clear to which one this refers. In fact, the whole of this discussion reads as if he were reporting hearsay, for it lacks in every respect the infinite detail of his usual descriptions. In any event, if the powder was introduced into the molten bullion, the effect would be to form some silver sulphides in a regulus of 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.