228 



BOOK VII. 



and it is nearly as long as the furnace ; only at the front end does it touch 

 the mouth of the furnace, everywhere else on the sides and at the back 

 there is a space of three digits, to allow the charcoal to lie in the open space 

 between it and the furnace. The muffle is as thick as a fairly thick earthen 

 jar ; its upper part is entire ; the back has two little windows, and each side 

 has two or three or even four, through which the heat passes into the scorifiers 

 and melts the ore. In place of little windows, some muffles have small holes, 

 ten in the back and more on each side. Moreover, in the back below the 

 Uttle windows, or small holes, there are cut away three semi-circular notches 

 half a digit high, and on each side there are four. The back of the muffle 

 is generally a little lower than the front. 



TOnMlllln«ll1ml^^lll^^v!'i^^ 



A — Broad little windows of muffle. B — Narrow ones. 



BACK THEREOF. 



C — Openings in the 



The crucibles differ in the materials from which they are made, because 

 they are made of either clay or ashes ; and those of clay, which we also call 

 " earthen," differ in shape and size. Some are made in the shape of a mod- 

 erately thick salver (scorifiers), three digits wide, and of a capacity of an 

 unda measure ; in these the ore mixed with fluxes is melted, and they are used 

 by those who assay gold or silver ore. Some are triangular and much 

 thicker and more capacious, holding five, or six, or even more unciae ; in 

 these copper is melted, so that it can be poured out, expanded, and tested 

 with fire, and in these copper ore is usually melted. 



The cupels are made of ashes ; like the preceding scorifiers they are 

 tray-shaped, and their lower part is very thick but their capacity is less. 

 In these lead is separated from silver, and by them assays are concluded. 

 Inasmuch as the assayers themselves make the cupels, something must 

 be said about the material from which they are made, and the method 

 of making them. Some make them out of all kinds of ordinary ashes ; these 

 are not good, because ashes of this kind contain a certain amount of fat, 

 whereby such cupels are easily broken when they are hot. Others make 

 them hkewise out of any kind of ashes which have been previously 

 leached ; of this kind are the ashes into which warm water has been infused 

 for the purpose of making lye. These ashes, after being dried in the sun or 

 a furnace, are sifted in a hair sieve ; and although warm water washes away the 



